RFR: 8317368: [JVMCI] SIGSEGV in JVMCIEnv::initialize_installed_code on libgraal [v2]

[Tom Rodriguez]

> This fixes some lurking issues with JVMCI and nmethod related both BarrierSetNMethod and the garbage collection of nmethods.  In particular the stack walking in c2v_iterateFrames visits many frames and needs a KeepStackGCProcessedMark for safety.  Additionally, JVMCI interacts with nmethods in complex ways and needs some sort of strong root during these interactions.  A new JavaThread field has been added that mirrors the way JVMTI keeps nmethods alive.

Tom Rodriguez has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge branch 'master' into tkr-nmethod-keep-alive
 - Move BarrierSetNMethod call into JVMCINMethodHandle::set_nmethod
 - 8317368: [JVMCI] SIGSEGV in JVMCIEnv::initialize_installed_code on libgraal

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Changes: https://git.openjdk.org/jdk/pull/17714/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17714&range=01
  Stats: 92 lines in 7 files changed: 72 ins; 8 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/17714.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17714/head:pull/17714

PR: https://git.openjdk.org/jdk/pull/17714