This relands API deprecation (without removing the implementation),
removal of NewFunction and BeforeCompile events, and removal of
DebugCommandProcessor tests.

The remaining portion of the original CLs can be relanded after the 4.7
branch point.

Original CLs:

https://codereview.chromium.org/2524323002
https://codereview.chromium.org/2531543002

BUG=v8:5510

Review-Url: https://codereview.chromium.org/2546473008
Cr-Commit-Position: refs/heads/master@{#41446}