RFR: 8339401: Optimize ClassFile load and store instructions [v2]

[Shaojin Wen]

> BytecodeHelpers' loadOpcode and storeOpcode are large methods with code size greater than 325, break it into multiple small methods and call them directly in DirectCodeBuilder

Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:

  suggestion from @liach

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/20739/files
  - new: https://git.openjdk.org/jdk/pull/20739/files/22565c58..58a15b38

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20739&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20739&range=00-01

  Stats: 109 lines in 1 file changed: 54 ins; 55 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/20739.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20739/head:pull/20739

PR: https://git.openjdk.org/jdk/pull/20739