RFR: 8360522: G1: Flag constraint functions for G1SATBBufferSize and G1UpdateBufferSize are skipped during argument validation

[Ivan Walulya]

Hi,

Please review this change to move constraint function execution for  G1SATBBufferSize and G1UpdateBufferSize  to AfterErgo. These functions rely on the UseG1GC flag to determine whether to apply checks. However, during the AtParse phase of argument handling, UseG1GC may not yet be processed, which causes the constraints to be skipped.

Testing:
`java -XX:G1SATBBufferSize=0 -version`
`G1SATBBufferSize (0) must be in range [1, 4294967295]`
`Error: Could not create the Java Virtual Machine.`
`Error: A fatal exception has occurred. Program will exit.`

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

Commit messages:
 - move to AfterErgo phase

Changes: https://git.openjdk.org/jdk/pull/25979/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25979&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360522
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/25979.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25979/head:pull/25979

PR: https://git.openjdk.org/jdk/pull/25979