Fix some corner cases of resynthesizing generic function types.

Fix some corner cases of resynthesizing generic function types.

We weren't always setting FunctionTypeImpl._isInstantiated correctly,
resulting in incorrect types in some rare corner cases.  I've added a
public `isInstantiated` getter so that we can check this more
thoroughly in unit tests.

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/0e2393f903bcc8a14217d5009b1dab1f3c044384

[Paul Berry, 2016-01-07 18:32:45]

paulberry@google.com changed reviewers:
+ scheglov@google.com

[scheglov, 2016-01-07 18:46:44]

LGTM

[Paul Berry, 2016-01-07 19:52:14]

Description was changed from

==========
Fix some corner cases of resynthesizing generic function types.

We weren't always setting FunctionTypeImpl._isInstantiated correctly,
resulting in incorrect types in some rare corner cases.  I've added a
public `isInstantiated` getter so that we can check this more
thoroughly in unit tests.
==========

to

==========
Fix some corner cases of resynthesizing generic function types.

We weren't always setting FunctionTypeImpl._isInstantiated correctly,
resulting in incorrect types in some rare corner cases.  I've added a
public `isInstantiated` getter so that we can check this more
thoroughly in unit tests.

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/0e2393f903bcc8a14217d5009b1dab1f3c044384
==========

[Paul Berry, 2016-01-07 19:52:15]

Committed patchset #1 (id:1) manually as
0e2393f903bcc8a14217d5009b1dab1f3c044384 (presubmit successful).