The following timed out in JDK15 tier6-comp-aot:

java/lang/String/Split.java
java/lang/Character/CheckUnicode.java
java/lang/Character/CheckProp.java

Here's a snippet from the Split.java log file:

#section:main
----------messages:(8/221)----------
command: main Split
reason: Assumed action based on file name: run main Split 
Mode: agentvm
Agent id: 9
Timeout refired 480 times
Timeout information:
--- Timeout information end.
elapsed time (seconds): 550.794
----------configuration:(9/634)*----------
Boot Layer
  class path: C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.0\\b01\\bundles\\jtreg_bin-5.0.zip\\jtreg\\lib\\javatest.jar 
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.0\\b01\\bundles\\jtreg_bin-5.0.zip\\jtreg\\lib\\jtreg.jar 
  patch:      java.base T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\patches\\java.base

Test Layer
  class path: T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\classes\\3\\java\\lang\\String\\Split.d
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String

----------rerun:(35/4247)*----------
cd 'T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\scratch\\0' && \\
JDK8_HOME=c:/ade/mesos/work_dir/jib-master/install/jdk/14/36/bundles/windows-x64/jdk-14_windows-x64_bin.zip/jdk-14 \\
JIB_DATA_DIR=c:/ade/mesos/work_dir/jib-master \\
JIB_HOME=c:/ade/mesos/work_dir/jib-master/install/com/oracle/java/jib/jib/3.0-SNAPSHOT/jib-3.0-SNAPSHOT-distribution.zip/jib-3.0-SNAPSHOT-distribution \\
JTREG_EXTRA_PROBLEM_LISTS=ProblemList-aot.txt \\
JTREG_KEYWORDS="!headful" \\
JTREG_VERBOSE=fail,error,time \\
PATH='C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.0\\b01\\bundles\\jtreg_bin-5.0.zip\\jtreg\\bin;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jpg\\infra\\builddeps\\gnumake-cygwin_x64\\4.0+1.0\\gnumake-cygwin_x64-4.0+1.0.tar.gz\\cygwin\\bin;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk\\14\\36\\bundles\\windows-x64\\jdk-14_windows-x64_bin.zip\\jdk-14\\bin;C:\\cygwin\\bin;C:\\cygwin\\usr\\local\\bin;C:\\cygwin\\bin;C:\\Windows\\System32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0' \\
SystemDrive=C: \\
SystemRoot='C:\\Windows' \\
TEMP='C:\\cygwin\\tmp' \\
TEST_IMAGE_DIR=c:/ade/mesos/work_dir/jib-master/install/jdk-15+26-1254/windows-x64-debug.test \\
TEST_IMAGE_GRAAL_DIR=c:/ade/mesos/work_dir/jib-master/install/jdk-15+26-1254/windows-x64-debug.test/hotspot/jtreg/graal \\
TMP='C:\\cygwin\\tmp' \\
TZ=Etc/GMT \\
_NT_SYMBOL_PATH=C:/ade/mesos/work_dir/jib-master/install/jdk-15+26-1254/windows-x64-debug.jdk_symbols/jdk-15/fastdebug/bin/;C:/ade/mesos/work_dir/jib-master/install/jdk-15+26-1254/windows-x64-debug.jdk_symbols/jdk-15/fastdebug/bin/server/ \\
windir='C:\\Windows' \\
    'c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\windows-x64-debug.jdk\\jdk-15\\fastdebug\\bin\\java' \\
        -Dtest.class.path.prefix='T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\classes\\3\\java\\lang\\String\\Split.d;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String' \\
        -Dtest.file='C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String\\Split.java' \\
        -Dtest.src='C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String' \\
        -Dtest.src.path='C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String' \\
        -Dtest.classes='T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\classes\\3\\java\\lang\\String\\Split.d' \\
        -Dtest.class.path='T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\classes\\3\\java\\lang\\String\\Split.d' \\
        -Dtest.vm.opts='-Xmx512m -XX:MaxRAMPercentage=3 -ea -esa -XX:+UnlockExperimentalVMOptions -XX:AOTLibrary=t:/testoutput/test-support/aot/jtreg_open_test_jdk_jdk_lang/java.base.dll' \\
        -Dtest.tool.vm.opts='-J-Xmx512m -J-XX:MaxRAMPercentage=3 -J-ea -J-esa -J-XX:+UnlockExperimentalVMOptions -J-XX:AOTLibrary=t:/testoutput/test-support/aot/jtreg_open_test_jdk_jdk_lang/java.base.dll' \\
        -Dtest.compiler.opts= \\
        -Dtest.java.opts='-server -ea -esa' \\
        -Dtest.jdk='c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\windows-x64-debug.jdk\\jdk-15\\fastdebug' \\
        -Dcompile.jdk='c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\windows-x64-debug.jdk\\jdk-15\\fastdebug' \\
        -Dtest.timeout.factor=4.0 \\
        -Dtest.root='C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk' \\
        -Dtest.nativepath='c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\windows-x64-debug.test\\jdk\\jtreg\\native' \\
        -classpath 'T:\\testoutput\\test-support\\jtreg_open_test_jdk_jdk_lang\\classes\\3\\java\\lang\\String\\Split.d;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+26-1254\\src.full\\open\\test\\jdk\\java\\lang\\String;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.0\\b01\\bundles\\jtreg_bin-5.0.zip\\jtreg\\lib\\javatest.jar;C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.0\\b01\\bundles\\jtreg_bin-5.0.zip\\jtreg\\lib\\jtreg.jar' \\
        Split
result: Error. Agent error: java.lang.Exception: Agent 9 timed out with a timeout of 480 seconds; check console log for any additional details


test result: Error. Agent error: java.lang.Exception: Agent 9 timed out with a timeout of 480 seconds; check console log for any additional details