I got tired of scan tests failing when they have an underspecified
pattern that matches LTO information, so I did a global replace for
the most common form of such scan patterns in the gcc.target/riscv
testsuite.

regression tested for:
    riscv-sim
    riscv-sim/-march=rv32gcv_zfh/-mabi=ilp32d/-ftree-vectorize/--param=riscv-autovec-preference=scalable
    riscv-sim/-march=rv32imac/-mabi=ilp32
    riscv-sim/-march=rv64gcv_zfh_zvfh_zba_zbb_zbc_zicond_zicboz_zawrs/-mabi=lp64d/-ftree-vectorize/--param=riscv-autovec-preferenc
e=scalable
    riscv-sim/-march=rv64imac/-mabi=lp64

Committed as obvious.