The plain typo:
diff -r 657dd0b09cbc test/jdk/java/foreign/TestArrays.java
--- a/test/jdk/java/foreign/TestArrays.java     Wed Jan 01 03:08:45 2020 +0100
+++ b/test/jdk/java/foreign/TestArrays.java     Fri Jan 10 09:51:51 2020 -0800
@@ -76,8 +76,8 @@
     static VarHandle shortHandle = shorts.varHandle(short.class, PathElement.sequenceElement());
     static VarHandle intHandle = ints.varHandle(int.class, PathElement.sequenceElement());
     static VarHandle floatHandle = floats.varHandle(float.class, PathElement.sequenceElement());
-    static VarHandle longHandle = doubles.varHandle(long.class, PathElement.sequenceElement());
-    static VarHandle doubleHandle = longs.varHandle(double.class, PathElement.sequenceElement());
+    static VarHandle longHandle = longs.varHandle(long.class, PathElement.sequenceElement());
+    static VarHandle doubleHandle = doubles.varHandle(double.class, PathElement.sequenceElement());
 
     static void initBytes(MemoryAddress base, SequenceLayout seq, BiConsumer<MemoryAddress, Long> handleSetter) {
         for (long i = 0; i < seq.elementCount().getAsLong() ; i++) {