This removes the deprecated flag in question which has been enabled by
default a while ago. All components can by now deal with activations of
a single function being mixed between Ignition and other compilers. The
maintenance overhead to support a mode that clears bytecode is no longer
warranted.

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

Review-Url: https://codereview.chromium.org/2475203003
Cr-Commit-Position: refs/heads/master@{#40776}