Replaces the graph-based liveness analyzer in the bytecode graph builder
with an initial bytecode-based liveness analysis pass, which is added to
the existing loop extent analysis.

Now the StateValues in the graph have their inputs initialised to
optimized_out, rather than being modified after the graph is built.

Review-Url: https://codereview.chromium.org/2523893003
Cr-Commit-Position: refs/heads/master@{#41344}