RFR: 8299847: RISC-V: Incorrect branch condition code in PrintOptoAssembly output

[Fei Yang]

Witnessed some incorrect branch condition code in PrintOptoAssembly output on RISC-V. While this won't affect release build, we should fix this for debug build. This also bumps the BRANCH_COST a little bit as I think control transfer instructions should have higher cost than integer computational instructions.

Testing: Tier1 tested on HiFive Unmatched board.

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Commit messages:
 - 8299847: RISC-V: Incorrect branch condition code in PrintOptoAssembly output

Changes: https://git.openjdk.org/jdk/pull/11919/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11919&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299847
  Stats: 34 lines in 1 file changed: 1 ins; 0 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/11919.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11919/head:pull/11919

PR: https://git.openjdk.org/jdk/pull/11919