RFR: 8302814: Delete unused CountLoopEnd instruct with CmpX [v4]

[SUN Guoyun]

> CountLoopEnd only for T_int, therefore the following instructs in riscv.ad are useless and should be deleted.
> 
> CountedLoopEnd cmp (CmpL op1 op2)
> CountedLoopEnd cmp (CmpU op1 op2)
> CountedLoopEnd cmp (CmpP op1 op2)
> CountedLoopEnd cmp (CmpN op1 op2)
> CountedLoopEnd cmp (CmpF op1 op2)
> CountedLoopEnd cmp (CmpD op1 op2)
> 
> and CountedLoopEnd with CmpU on x86*.ad, aarch64.ad ar useless also.
> 
> Please help review it.
> 
> Thanks.

SUN Guoyun has updated the pull request incrementally with one additional commit since the last revision:

  8302814: Delete unused CountLoopEnd instruct with CmpX

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12648/files
  - new: https://git.openjdk.org/jdk/pull/12648/files/d2aa86ee..1c891757

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12648&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12648&range=02-03

  Stats: 59 lines in 2 files changed: 0 ins; 59 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/12648.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12648/head:pull/12648

PR: https://git.openjdk.org/jdk/pull/12648