This CL updates Tint to use 'bitcast' instead of 'as' for the OpBitcast
conversions.
Bug: tint:241
Change-Id: I53a80de10421b2d9cc009527eebe5ff07e1285c2
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/28801
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: David Neto <dneto@google.com>