RFR: 8343767: Enumerate StubGen blobs, stubs and entries and generate code from declarations [v5]

[Andrew Dinn]

> Implementation of JDK-8343767

Andrew Dinn 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 55 additional commits since the last revision:

 - Merge branch 'master' into iterate_stubs
 - fix element sizes in s390 copy routines
 - fix stub is and align flags for s390
 - fix comments and remove unused stubid on riscv
 - locate super lookup stubs in same blob for all arches
 - do verification under ifdef ASSERT
 - fix yet more problems with s390 stubs
 - better error notification
 - fix more problems with s390 stubs
 - Verify stubs are generated in correct blob
 - ... and 45 more: https://git.openjdk.org/jdk/compare/b619c954...e21268c4

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21957/files
  - new: https://git.openjdk.org/jdk/pull/21957/files/0f8eb111..e21268c4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21957&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21957&range=03-04

  Stats: 13209 lines in 505 files changed: 5122 ins; 5639 del; 2448 mod
  Patch: https://git.openjdk.org/jdk/pull/21957.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21957/head:pull/21957

PR: https://git.openjdk.org/jdk/pull/21957