Faster invocation of fields as methods.

Faster invocation of fields as methods.

Until now there was a large discrepancy between

x.f() and
(x.f)()

This CL makes x.f() as fast as (x.f)() by automatically
generating  a intermediate dispatcher function that loads
the field and invokes the result as a closure.

The approach resembles the one taken for fast noSuchMethod
invocation and reuses the same per-class cache
of dispatcher functions.

It also fixes a bug in the debugger so that VM-generated 
implicit dispatcher functions (like for noSuchMethod, or
field-as-method invocation) don't show up the debuggers
stack trace.

BUG=https://code.google.com/p/dart/issues/detail?id=11041
R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25001

[srdjan, 2013-07-11 17:24:55]

Please add tests. Otherwise LGTM!

[hausner, 2013-07-11 22:37:53]

DBC: would be nice if you also added a debugger test similar to
standalone/debugger/basic_debugger_test.dart

[Florian Schneider, 2013-07-15 11:04:17]

Done. Added debugger test. Existing tests already cover invocation of fields as
methods.

[Florian Schneider, 2013-07-15 11:12:21]

Committed patchset #2 manually as r25001 (presubmit successful).

[hausner, 2013-07-15 15:28:23]

Nice, thank you!