JDK-8227123 updated the test so that experimental and diagnostic flags are also tested. We now see a crash when testing an experimental flag:

TEST FAILED: Error processing option SurvivorAlignmentInBytes with valid value '-server -XX:+UseParallelGC -XX:SurvivorAlignmentInBytes=2147483648'! JVM output reports a fatal error. JVM exited with code 134 [0x86]!

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (open/src/hotspot/share/gc/parallel/psPromotionLAB.inline.hpp:45), pid=25256, tid=25441
# assert(is_aligned(obj, SurvivorAlignmentInBytes) && is_object_aligned(new_top)) failed: checking alignment
#
# JRE version: Java(TM) SE Runtime Environment (14.0+8) (fastdebug build 14-ea+8-243)

Unclear whether the test needs fixing or the range for the flag needs to be more constrained. Assigning to runtime initially to consider that question.