This change introduces a pipeline for the final stages of
bytecode generation.

The peephole optimizer is made distinct from the BytecodeArrayBuilder.

A new BytecodeArrayWriter is responsible for writing bytecode. It
also keeps track of the maximum register seen and offers a potentially
smaller frame size.

R=rmcilroy@chromium.org
LOG=N
BUG=v8:4280

Review-Url: https://codereview.chromium.org/1947403002
Cr-Commit-Position: refs/heads/master@{#36220}