[Isolates] Merge (7253,7263] from bleeding_edge.

[Isolates] Merge (7253,7263] from bleeding_edge.

r7263 | Make Script.prototype.nameOrSourceURL use indexOf search first
        before trying to match with a RegExp.
r7262 | Revert r7258 and r7260.
r7261 | Fix presumbit warning after r7259
r7260 | Fix build.
r7259 | Dramatically speed up detailed heap snapshot generation.
r7258 | Make exception thrown via v8 public API propagate to
        v8::TryCatch as JS thrown exceptions do.

Committed: http://code.google.com/p/v8/source/detail?r=7264

[Vitaly Repeshko, 2011-03-18 14:00:52]

Oops, up to r7263, not r7264.

[antonm, 2011-03-18 14:06:58]

Rubberstamp LGTM