[lworld] RFR: 8281763: Support Valhalla class file features in asmtools [v2]

[Dan Smith]

> Modifying the Valhalla repo's fork of asmtools to implement Valhalla class file features:
> 
> - ACC_VALUE, ACC_PERMITS_VALUE, and ACC_PRIMITIVE 
> - Preload attribute 
> - aconst_init & withfield instructions 
> - Unnamed factory methods 
> - Q descriptors
> 
> Mainly relevant to the `jasm` tool, but there are also some interactions with `jdis` and `jdec`. No impact on `jcod`.

Dan Smith has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 13 commits:

 - Merge branch 'asmtools' into asmtools-valhalla
 - Merge branch 'lworld' into asmtools
 - 8281880: AsmTools driver uses wrong implementation classes
 - Merge branch 'asmtools' into asmtools-valhalla
 - Merge branch 'lworld' into asmtools
 - Modified asmtools files
 - AsmTools updates for Valhalla features
 - Merge branch 'lworld' into asmtools
 - Fix trailing whitespace
 - Added usage comment
 - ... and 3 more: https://git.openjdk.java.net/valhalla/compare/2c8ecdb0...634c132f

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

Changes: https://git.openjdk.java.net/valhalla/pull/647/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=647&range=01
  Stats: 189 lines in 14 files changed: 165 ins; 6 del; 18 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/647.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/647/head:pull/647

PR: https://git.openjdk.java.net/valhalla/pull/647