[lworld] RFR: 8376145: [lworld] Enable SubstitutabilityTest.java with AOTJDK

[Matias Saavedra Silva]

valhalla/valuetypes/SubstitutabilityTest.java is not compatible with AOTJDK due to the use of -Xshare:off. This test should still be run with AOT so we can split the test cases and only problem list the configuration that is incompatible.

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Commit messages:
 - Add to problem list again
 - Fix substitutability test for AOTJDK

Changes: https://git.openjdk.org/valhalla/pull/1953/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1953&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376145
  Stats: 11 lines in 2 files changed: 10 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1953.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1953/head:pull/1953

PR: https://git.openjdk.org/valhalla/pull/1953