- Adds unary Reverse shuffles (swizzles): S32x2Reverse, S16x4Reverse,
  S16x2Reverse, S8x8Reverse, S8x4Reverse, S8x2Reverse. Reversals are
  done within the sub-vectors that prefix the opcode name, e.g. S8x2
  reverses the 8 consecutive pairs in an S8x16 vector.

- Adds binary Zip (interleave) left and right half-shuffles to return a
  single vector: S32x4ZipLeft, S32x4ZipRightS16x8ZipLeft, S16x8ZipRight,
  S8x16ZipLeft, S8x16ZipRight.

- Adds binary Unzip (de-interleave) left and right half shuffles to return
  a single vector: S32x4UnzipLeft, S32x4UnzipRight, S16x8UnzipLeft,
  S16x8UnzipRight, S8x16UnzipLeft, S8x16UnzipRight.

- Adds binary Transpose left and right half shuffles to return
  a single vector: S32x4TransposeLeft, S32x4TransposeRight,
  S16x8TransposeLeft, S16xTransposeRight, S8x16TransposeLeft,
  S8x16TransposeRight.

- Adds binary Concat (concatenate) byte shuffle: S8x16Concat #bytes to
  paste two vectors together.

LOG=N
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2801183002
Cr-Commit-Position: refs/heads/master@{#44734}