[vectorIntrinsics] RFR: Merge panama-vector:vector-unstable

[Sandhya Viswanathan]

Merge vector-unstable changes into vectorIntrinsics branch.

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Commit messages:
 - Merge fix
 - Merge
 - Merge panama-vector:master
 - 8254263: Remove special_runtime_exit_condition() check from ~ThreadInVMForHandshake()
 - 8254777: Remove unimplemented Management::get_loaded_classes
 - 8254781: Remove unimplemented ClassFieldMap::compute_field_count
 - 8254780: EnterInterpOnlyModeClosure::completed() always returns true
 - 8223347: Integration of Vector API (Incubator)
 - 8254789: ProblemList compiler/graalunit/HotspotTest.java
 - 8249623: test @ignore-d due to 7013634 should be returned back to execution
 - ... and 362 more: https://git.openjdk.java.net/panama-vector/compare/40c2915a...4f3d4058

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - vectorIntrinsics: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=14&range=00.0
 - panama-vector:vector-unstable: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=14&range=00.1

Changes: https://git.openjdk.java.net/panama-vector/pull/14/files
  Stats: 93653 lines in 3357 files changed: 38044 ins; 40528 del; 15081 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/14.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/14/head:pull/14

PR: https://git.openjdk.java.net/panama-vector/pull/14