[riscv-port] RFR: 8279914: riscv: Wrong result caused by incorrect use of iregL2I operand in some c2 match rules [v3]

[Feilong Jiang]

> This PR fix the issue that incorrect use if iRegL2I operand in some c2 match rules.

Feilong Jiang has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains two new commits since the last revision:

 - update commments rs2 to src2
 - 8279914: riscv: Wrong result caused by incorrect use of iregL2I operand in some c2 match rules

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Changes:
  - all: https://git.openjdk.java.net/riscv-port/pull/44/files
  - new: https://git.openjdk.java.net/riscv-port/pull/44/files/7fe8898f..fab29f8c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=44&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=44&range=01-02

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/riscv-port/pull/44.diff
  Fetch: git fetch https://git.openjdk.java.net/riscv-port pull/44/head:pull/44

PR: https://git.openjdk.java.net/riscv-port/pull/44