Add support for F32x4Splat, F32x4ExtractLane,
F32x4ReplaceLane, F32x4SConvertI32x4, F32x4UConvertI32x4
operations for mips32 and mips64 architectures.

BUG=

Note: Depends on https://codereview.chromium.org/2753903004/
Review-Url: https://codereview.chromium.org/2780503002
Cr-Commit-Position: refs/heads/master@{#44359}