[lworld] RFR: 8348606: [lworld] Substitutability test may perform heap allocations [v3]

[Chen Liang]

> Update substitutability test to use MethodHandles that access independent primitive/pointer instead heap reallocated copies of inlined values with an object header. Need long-term solution for user MethodHandle that accesses nested values in the future; hope the intrinsics can help in the future.
> 
> Testing: test/jdk/valhalla and test/hotspot/jtreg/*/valhalla, tier 1-3 tests running.

Chen Liang 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 four additional commits since the last revision:

 - Merge branch 'lworld' of https://github.com/openjdk/valhalla into fix/vo-obj-getters
 - Merge branch 'lworld' of https://github.com/openjdk/valhalla into fix/vo-obj-getters
 - Fix redundant debug and failing IO test
 - 8348606: [lworld] Substitutability test may perform heap allocations

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1364/files
  - new: https://git.openjdk.org/valhalla/pull/1364/files/4d6a7d5c..ae2c70ee

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1364&range=02
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1364&range=01-02

  Stats: 157312 lines in 3353 files changed: 76372 ins; 55017 del; 25923 mod
  Patch: https://git.openjdk.org/valhalla/pull/1364.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1364/head:pull/1364

PR: https://git.openjdk.org/valhalla/pull/1364