This removes the CompilationInfoWithZone class, which was used to
allocate a CompilationInfo on the C-heap. By now the CompilationJob is
the single object being allocated on the C-heap and passed between the
main thread and the compilation thread. Structs requiring destruction
can be embedded within that CompilationJob. This simplifies involved
lifetimes by coupling all lifetimes to one single object.

R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/1930773003
Cr-Commit-Position: refs/heads/master@{#35936}