The test ShowRegistersOnAssertTest fails on ARM32, because on that platform, the BREAKPOINT macro emits a "bkpt" instruction [1]. BREAKPOINT is used at the end of every assert [2] and because the test suppresses errors, the bkpt instruction is executed.
Because of that, the JVM receives SIGTRAP and core dumps:

$ ./jdk-fastdebug-bkpt/bin/java -XX:+UnlockDiagnosticVMOptions -Xmx100M -XX:-CreateCoredumpOnCrash -XX:ErrorHandlerTest=3 -XX:SuppressErrorAt=/vmError.cpp -XX:-ShowRegistersOnAssert -version
Trace/breakpoint trap (core dumped)

As far as I can see, ARM32 is the only platform on which the BREAKPOINT macro has a special definition.

[1] https://hg.openjdk.java.net/jdk/jdk/file/219ec11136d9/src/hotspot/cpu/arm/globalDefinitions_arm.hpp#l61
[2] https://hg.openjdk.java.net/jdk/jdk/file/219ec11136d9/src/hotspot/share/utilities/debug.hpp#l59