Update clang version to clang-r498229b

Now built with MLGO. This reduces the total Clang invocation time for
building AOSP by 0.7%.

    TOOLCHAIN_RUSAGE_OUTPUT=/tmp/rusage.txt m -j32
    PGO + LTO + BOLT          83839.78s
    MLGO + PGO + LTO + BOLT   82949.30s

Test: presubmit
Bug: 293616148
Change-Id: I5364c341520172e8e1acafb4aa3330922805ac0e