[jdk17u-dev] RFR: 8283784: java_lang_String::as_platform_dependent_str stores to oop in native state

[jyma22]

Hi all,

This pull request contains a backport of commit [c9a469a](https://github.com/openjdk/jdk/commit/c9a469a4591002e7f51317a8494a2df902db5bfa) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by David Holmes on Mar 30 2022 and was reviewed by Kim Barrett, Aleksey Shipilev, and Stefan Karlsson.

Testing: jtreg tier 1-3 as sanity test

Thanks!

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Commit messages:
 - Merge branch 'JDK-8283784-ctw-gc-improv' of github.com:jyma22/jdk17u-dev into JDK-8283784-ctw-gc-improv
 - 8283784: java_lang_String::as_platform_dependent_str stores to oop in native state
 - Backport c9a469a4591002e7f51317a8494a2df902db5bfa

Changes: https://git.openjdk.org/jdk17u-dev/pull/3988/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3988&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8283784
  Stats: 7 lines in 1 file changed: 3 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3988.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3988/head:pull/3988

PR: https://git.openjdk.org/jdk17u-dev/pull/3988