RFR: 8305990: Stripping debug info of ASM 9.5 fails [v12]

[Adam Sotona]

> Classfile API didn't handle transformations of class files version 50 and below correctly. 
> 
> Proposed fix have two parts: 
> 1. Inflation of branch targets does not depend on StackMapTable attribute presence for class file version 50 and below. Alternative fallback implementation is provided. 
> 2. StackMapTable attribute is not generated for class file versions below 50.
> 
> StackMapsTest is also extended to test this patch.
> 
> Please review.
> 
> Thanks,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  implemented failover stackmap generation for class version 50
  fixed StackMapGenerator error debug print + added clone constructor to SplitConstantPool
  adjusted and extended related tests

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13478/files
  - new: https://git.openjdk.org/jdk/pull/13478/files/6fbd2719..795314a2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13478&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13478&range=10-11

  Stats: 54 lines in 5 files changed: 31 ins; 11 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/13478.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13478/head:pull/13478

PR: https://git.openjdk.org/jdk/pull/13478