RFR: 8316415: Parallelize sun/security/rsa/SignedObjectChain.java subtests

[Michal Sobierski]

sun/security/rsa/SignedObjectChain.java is very slow when run with C1, I suspect because some crypto intrinsics are only implemented in C2. Commit contains changes made to parallelize it.

Comparison of before and after parallelization:
time make test TEST=jdk/sun/security/rsa/SignedObjectChain.java TEST_VM_OPTS="-XX:+UseParallelGC -XX:TieredStopAtLevel=1"
before:   270.72s user 4.88s system 108% cpu 4:14.43 total
after:   410.76s user 7.50s system 555% cpu 1:15.23 total

time make test TEST=jdk/sun/security/rsa/SignedObjectChain.java TEST_VM_OPTS="-XX:+UseParallelGC"
before:   63.67s user 4.67s system 161% cpu 42.424 total
after:   130.36s user 7.47s system 585% cpu 23.526 total

time make test TEST=jdk/sun/security/rsa/SignedObjectChain.java TEST_VM_OPTS="-XX:+UseShenandoahGC -XX:TieredStopAtLevel=1"
before:   281.99s user 5.54s system 108% cpu 4:24.09 total
after:   386.98s user 8.62s system 496% cpu 1:19.73 total

time make test TEST=jdk/sun/security/rsa/SignedObjectChain.java TEST_VM_OPTS="-XX:+UseShenandoahGC"
before:   65.86s user 5.05s system 156% cpu 45.215 total
after:   135.90s user 7.66s system 585% cpu 24.502 total

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Commit messages:
 - 8316415: Parallelize sun/security/rsa/SignedObjectChain.java subtests

Changes: https://git.openjdk.org/jdk/pull/15860/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15860&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316415
  Stats: 97 lines in 1 file changed: 80 ins; 13 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/15860.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15860/head:pull/15860

PR: https://git.openjdk.org/jdk/pull/15860