RFR: 8354871: Replace stack map frame type magics with constants [v3]

[Francesco Andreuzzi]

> In this PR I introduce some constants in `StackMapGenerator`. No change in logic is expected.
> 
> Passes tests in `jdk/classfile`.

Francesco Andreuzzi has updated the pull request incrementally with one additional commit since the last revision:

  inclusive

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27029/files
  - new: https://git.openjdk.org/jdk/pull/27029/files/4a9bf431..0c6c04b7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27029&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27029&range=01-02

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27029.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27029/head:pull/27029

PR: https://git.openjdk.org/jdk/pull/27029