Current implementation of the pextrw instruction is the legacy SSE2 instruction in the assembler (66 0F C5), and SSE4 implementation(66 0F 3A 15) in disasm-x64.cc, this causes incorrect instruction encodings to be printed when using --print-code flag for debug, in this case, causes over flow of bytes, and subsequent instructions to be incorrectly disassembled. Fixing to use SSE4 encodings in the assembler cosistent with pextrb, pextrd.

R=bbudge@chromium.org, mtrofin@chromium.org

Review-Url: https://codereview.chromium.org/2771513002
Cr-Commit-Position: refs/heads/master@{#44047}