RFR: 8301814: RISCV: Delete unused CountLoopEnd instruct with CmpX

[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)

Please help review it.

Thanks.

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Commit messages:
 - Merge branch 'openjdk:master' into 8302814
 - 8302814: Delete unused CountLoopEnd instruct with CmpX

Changes: https://git.openjdk.org/jdk/pull/12648/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12648&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301814
  Stats: 477 lines in 1 file changed: 0 ins; 477 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