[RISCV] Fix ordering of CHECK prefixes in some tests to mitigate UTC bug. NFCI (#181259)

This patch fixes the exact same problem as #173125 . Where certain order
of CHECK prefixes will somehow causing UTC to incorrectly (re)generate
surplus check lines and failed the tests.

GitOrigin-RevId: c6f24719afa3d76f12a26604936898cbfc4568a5