The AST-based graph builder is by now only used for asm.js code. This
change hard-codes this assumption into the compilation pipeline and
hence allows us to remove support pertaining to deoptimization from
optimized code that was not derived from bytecode.

R=jarin@chromium.org
BUG=v8:6409

Change-Id: I1138f16f663db5b9ee34e3110184067b8fcffc8b
Reviewed-on: https://chromium-review.googlesource.com/531026
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45887}