RFR: 8339113: AccessFlags can be u2 in metadata [v3]

[Coleen Phillimore]

> Please review this change that makes AccessFlags and modifier_flags u2 types and removes the last remnants of Hotspot adding internal access flags.  This change moves AccessFlags and modifier_flags in Klass to alignment gaps saving 16 bytes.  From pahole: so it's a bit better.
> 
> before:
> 
>         /* size: 216, cachelines: 4, members: 25, static members: 17 */
>         /* sum members: 194, holes: 3, sum holes: 18 */
> 
> 
> after:
> 
>         /* size: 200, cachelines: 4, members: 25, static members: 17 */
>         /* sum members: 188, holes: 4, sum holes: 12 */
> 
> 
> We may eventually move the modifiers to java.lang.Class but that's WIP.
> 
> Tested with tier1-7 on oracle platforms.  Did test builds on other platforms (please try these changes ppc/arm32 and s390).  Also requires minor Graal changes.

Coleen Phillimore 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 eight additional commits since the last revision:

 - Fixed bug.
 - Fix merge and compilation errors.
 - Merge branch 'master' into access-flags
 - Renamed AccessFlags.as_int() to as_unsigned_short(), moved masks for method, field and class modifiers into AccessFlags. Change ciFlags to use AccessFlags.
 - Update src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp
   
   Co-authored-by: David Holmes <62092539+dholmes-ora at users.noreply.github.com>
 - Update src/hotspot/share/opto/library_call.cpp
   
   Co-authored-by: David Holmes <62092539+dholmes-ora at users.noreply.github.com>
 - Remove JVM_ACC_WRITTEN_FLAGS because they are all written in the classfile now.
 - 8339113: AccessFlags can be u2 in metadata

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22246/files
  - new: https://git.openjdk.org/jdk/pull/22246/files/cc69a3f2..522ade8c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22246&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22246&range=01-02

  Stats: 5573 lines in 201 files changed: 3545 ins; 1398 del; 630 mod
  Patch: https://git.openjdk.org/jdk/pull/22246.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22246/head:pull/22246

PR: https://git.openjdk.org/jdk/pull/22246