Adds an optimization to not emit unnecessary jumps and dead code in If,
For, While, and do-while statments. When the value of condition is known
at compile time, the code is emitted only for the paths that can be taken.
For example, when the condition is known to be true in an if statmenet
only then block is generated.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1414193006

Cr-Commit-Position: refs/heads/master@{#31715}