Fix for use-after-free of reload context

Fix for use-after-free of reload context

Delete the reload context after the last use. My first attempt did not work
with our unit test framework for reload cc tests.  When running unit tests
the reload context is needed for longer, and deleted separately.

BUG=#26895
R=johnmccutchan@google.com

Committed: https://github.com/dart-lang/sdk/commit/25070b85b1142fd30ecd7442af11b12aa90cc9f6

[Florian Schneider, 2016-07-20 00:00:55]

fschneider@google.com changed reviewers:
+ johnmccutchan@google.com

[Florian Schneider, 2016-07-20 00:00:56]

This fixes the original use-after-free and works with the unit tests. Ideally,
I'd like to get rid of test_mode(). But it seems this requires more refactoring,
so I'd like to land a fix for the test failures first.

[Florian Schneider, 2016-07-20 00:37:16]

Renaming and small simplification.

[Cutch, 2016-07-20 00:44:39]

lgtm

[Florian Schneider, 2016-07-20 01:29:01]

Description was changed from

==========
Fix for use-after-free of reload context

Delete the reload context after the last use. My first attempt did not work
with our unit test framework for reload cc tests.  When running unit tests
the reload context is needed for longer, and deleted separately.

BUG=#26895
==========

to

==========
Fix for use-after-free of reload context

Delete the reload context after the last use. My first attempt did not work
with our unit test framework for reload cc tests.  When running unit tests
the reload context is needed for longer, and deleted separately.

BUG=#26895
R=johnmccutchan@google.com

Committed:
https://github.com/dart-lang/sdk/commit/25070b85b1142fd30ecd7442af11b12aa90cc9f6
==========

[Florian Schneider, 2016-07-20 01:29:02]

Committed patchset #2 (id:20001) manually as
25070b85b1142fd30ecd7442af11b12aa90cc9f6 (presubmit successful).