[jdk11u-dev] RFR: 8264016: [JVMCI] add some thread local fields for use by JVMCI

[Severin Gehwolf]

Please review this JVMCI-related backport for OpenJDK 11u. It adds some thread-local fields and is useful so as to be able to run graal js on stock OpenJDK. The JDK 17 patch didn't apply clean due to context differences, which got fairly trivially resolved.

Testing: test/hotspot/jtreg/compiler/jvmci and manual test using upstream Graal unit test.

Thoughts?

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Commit messages:
 - Backport 182b11c31aa1d697ed254042c3350330ca3ac6e4

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/278/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=278&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264016
  Stats: 14 lines in 3 files changed: 14 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/278.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/278/head:pull/278

PR: https://git.openjdk.java.net/jdk11u-dev/pull/278