RFR: 8260716 : Assert in MacroAssembler::clear_mem with -XX:-IdealizeClearArrayNode [v4]

[Jamsheed Mohammed C M]

> [8257772](https://bugs.openjdk.java.net/browse/JDK-8257772) added a new rule(rep_stos_im), modified old rules(rep_stos) missed adding proper predicates relating to UseAVX and supports_avx512vlbw
> 
> Testing : Running, added in JBS

Jamsheed Mohammed C M has updated the pull request incrementally with one additional commit since the last revision:

  Adding test

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3035/files
  - new: https://git.openjdk.java.net/jdk/pull/3035/files/f5eed2a1..377cd2f3

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3035&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3035&range=02-03

  Stats: 45 lines in 1 file changed: 45 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3035.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3035/head:pull/3035

PR: https://git.openjdk.java.net/jdk/pull/3035