This solves a bug discovered with fast accessors, where a pre-age prologue
was written into a stub. Since StaticMarkingVisitor<.>::IsFlushable will
only flush Code::FUNCTION [1], we'll restrict GeneratePreagedPrologue to
functions, too, instead of adding a Code::STUB restriction.

Also, generalize api accessor test cases to --optimize-for-size.
Also, fix CompilationCacheCachingBehavior for --optimize-for-size.

[1] https://code.google.com/p/chromium/codesearch#chromium/src/v8/src/heap/objects-visiting-inl.h&l=629-632

R=epertoso
BUG=

Review URL: https://codereview.chromium.org/1580323003

Cr-Commit-Position: refs/heads/master@{#33291}