RFR: 8302795: Shared archive failed on old version class with jsr bytecode [v2]

[Calvin Cheung]

> Please review this simple fix for avoid writing in to CDS archive during runtime while loading a shared old class (major_version < 50) with methods containg the jsr byte code.
> Otherwise, JVM crashes with the following message in the hs err log:
> `Error accessing class data sharing archive. Mapped file inaccessible during execution, possible disk/network problem.`
> 
> Passed tiers 1 - 4 testing.

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  make the _methods array writable during dump time for old classes with jsr bytecode

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12752/files
  - new: https://git.openjdk.org/jdk/pull/12752/files/6a8b5251..ecea6558

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12752&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12752&range=00-01

  Stats: 40 lines in 3 files changed: 30 ins; 8 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12752.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12752/head:pull/12752

PR: https://git.openjdk.org/jdk/pull/12752