port ddc626e1 (r34546)

  original commit message:
  I64Shl is lowered to a new turbofan operator, WasmWord64Shl. The new
  operator takes 3 inputs, the low-word input, the high-word input, and
  the shift, and produces 2 output, the low-word output and the high-word
  output.

  At the moment I implemented the lowering only for ia32, but I think the
  CL is already big enough. I will add the other platforms in separate
  CLs.

BUG=

Review URL: https://codereview.chromium.org/1773083002

Cr-Commit-Position: refs/heads/master@{#34591}