REGRESSION (r143759): 40% JSBench regression, 20% Octane/closure regression, 40% Octane/jquery regression, 2% Octane regression
https://bugs.webkit.org/show_bug.cgi?id=111797

Reviewed by Oliver Hunt.

The bot's testing configuration stresses the cache's starting guess
of 1MB.

This patch removes any starting guess, and just uses wall clock time
to discover the initial working set size of an app, in code size.

* runtime/CodeCache.cpp:
(JSC::CodeCacheMap::pruneSlowCase): Update our timer as we go.

Also fixed a bug where pruning from 0 to 0 would hang -- that case is
a possibility now that we start with a capacity of 0.

* runtime/CodeCache.h:
(CodeCacheMap):
(JSC::CodeCacheMap::CodeCacheMap):
(JSC::CodeCacheMap::add):
(JSC::CodeCacheMap::prune): Don't prune if we're in the middle of
discovering the working set size of an app, in code size.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145171 268f45cc-cd09-0410-ab3c-d52691b4dbfc