RFR: 8339113: AccessFlags can be u2 in metadata [v2]

[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 incrementally with two additional commits since the last revision:

 - 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>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22246/files
  - new: https://git.openjdk.org/jdk/pull/22246/files/3106bdd3..cc69a3f2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22246&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22246&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 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