RFR: 8311071: Avoid SoftReferences in LambdaFormEditor and MethodTypeForm when storing heap objects into AOT cache [v5]

[Ioi Lam]

> This is the 6th PR for [JEP 483: Ahead-of-Time Class Loading & Linking](https://bugs.openjdk.org/browse/JDK-8315737).
> 
> The implementation of java.lang.invoke uses SoftReferences so that unused MethodHandles, LambdaForms, etc, can be garbage collected.
> 
> However, if we want to store java.lang.invoke objects in the AOT cache ([JDK-8293336](https://bugs.openjdk.org/browse/JDK-8293336), the final step in JEP 493), it's difficult to cache these SoftReferences -- SoftReferences in turn point to ReferenceQueues, etc, which have dependencies on the current execution state (Threads, etc) which are difficult to cache.
> 
> The proposal is to add a new flag: `MethodHandleStatics.NO_SOFT_CACHE`. When this flag is true, we avoid using SoftReferences, and store a direct reference to the target object instead.
> 
> [JDK-8293336](https://bugs.openjdk.org/browse/JDK-8293336) stores only java.lang.invoke objects that refer to classes loaded by the boot/platform/app loaders. These classes are never unloaded, so it's not necessary to point to them using SoftReferences.
> 
> This RFE modifies only the LambdaFormEditor and MethodTypeForm classes, as that's the minimal modification required by [JDK-8293336](https://bugs.openjdk.org/browse/JDK-8293336).
> 
> ---
> See [here](https://bugs.openjdk.org/browse/JDK-8315737) for the sequence of dependent RFEs for implementing JEP 483.

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 11 additional commits since the last revision:

 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yam/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - @liach and @cl4es comments
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yam/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - @dholmes-ora review comments
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yam/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yam/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - Do not use system property to limit usage to only CDS static dumps
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yam/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yak/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - Merge branch 'jep-483-step-05-8293337-archive-method-handle-intrinsics' of /jdk3/yak/open into jep-483-step-06-8311071-avoid-soft-refs-in-java-lang-invoke
 - ... and 1 more: https://git.openjdk.org/jdk/compare/34badfeb...b383d24b

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21049/files
  - new: https://git.openjdk.org/jdk/pull/21049/files/1c98bfab..b383d24b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21049&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21049&range=03-04

  Stats: 174327 lines in 1399 files changed: 158717 ins; 8139 del; 7471 mod
  Patch: https://git.openjdk.org/jdk/pull/21049.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21049/head:pull/21049

PR: https://git.openjdk.org/jdk/pull/21049