RFR: 8343767: Enumerate StubGen blobs, stubs and entries and generate code from declarations [v11]

[Andrew Dinn]

> Implementation of JDK-8343767

Andrew Dinn has updated the pull request incrementally with four additional commits since the last revision:

 - allow repeated entries rather than stubs
 - correct error in stub routines fill test
 - remove unused ppc stub
 - fix errors in s390 arraycopy code

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21957/files
  - new: https://git.openjdk.org/jdk/pull/21957/files/2bc580ce..691d6ad8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21957&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21957&range=09-10

  Stats: 425 lines in 17 files changed: 70 ins; 240 del; 115 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