- Reorganizes shuffle tests into tabular form.
- Adds a test that composes random numbers of random shuffles to
  make new shuffles.
- Adds a test that generates functions to compute a complex expression
  consisting of shuffles, and compares interpreter results to compiled
  code results.
- Fixes a problem with temp register exhaustion on ARM 32-bit.
- Matches identity shuffles (returning first or second operand
  unchanged) and uses EmitIdentity() for these.

Bug: v8:6020
Change-Id: Ie41c14fee52a7406b1d32e731e050096400e12f5
Reviewed-on: https://chromium-review.googlesource.com/1119567
Commit-Queue: Bill Budge <bbudge@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54446}