RFR: 8343703: Symbol name cleanups after JEP 479 [v3]

[David Holmes]

> After JEP 479 ([JDK-8339783](https://bugs.openjdk.org/browse/JDK-8339783) was integrated, the handling of certain symbol lookup code can be simplified. The old code needed to support 32-bit Windows, where names had a trailing `@<number>`. When this special case now is removed, some streamlining is possible. Specifically these arrays:
> 
> #define JNI_ONLOAD_SYMBOLS {"JNI_OnLoad"}
> #define JNI_ONUNLOAD_SYMBOLS {"JNI_OnUnload"}
> #define JVM_ONLOAD_SYMBOLS {"JVM_OnLoad"}
> #define AGENT_ONLOAD_SYMBOLS {"Agent_OnLoad"}
> #define AGENT_ONUNLOAD_SYMBOLS {"Agent_OnUnload"}
> #define AGENT_ONATTACH_SYMBOLS {"Agent_OnAttach"}
> 
> are all singletons and so the actual strings can just be inlined directly into the code that uses them.
> 
> Testing:
> - GHA
> - Tiers 1-4 sanity
> - 
> Thanks

David Holmes has updated the pull request incrementally with two additional commits since the last revision:

 - Merge branch '8343703-jni-symbol' of github.com:dholmes-ora/jdk into 8343703-jni-symbol
 - Fix indent

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22380/files
  - new: https://git.openjdk.org/jdk/pull/22380/files/c38bb48f..64ecc3b9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22380&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22380&range=01-02

  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/22380.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22380/head:pull/22380

PR: https://git.openjdk.org/jdk/pull/22380