CLI driver test re-enablement (#25001).

CLI driver test re-enablement (#25001).

Another stab.  The rub, I *think*, to our failures are unexpected calls to `exit()` on the bots (that are not reproducing locally).  These fixes should address that (and fix error stream handling along the way).

* fixes test setup and teardown to ensure exit handling is properly managed.
* fixes driver source to use the `exitHandler` and `errorSink` consistently

BUG=
R=keertip@google.com, scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/5a57d6e8dcf24741dd8d099e971a189563b302f5

[pquitslund, 2015-12-14 19:14:17]

pquitslund@google.com changed reviewers:
+ keertip@google.com, scheglov@google.com

[scheglov, 2015-12-14 19:17:08]

LGTM

[keertip, 2015-12-14 19:18:54]

lgtm

[pquitslund, 2015-12-14 21:08:51]

Description was changed from

==========
CLI driver test re-enablement (#25001).

Another stab.  The rub, I *think*, to our failures are unexpected calls to
`exit()` on the bots (that are not reproducing locally).  These fixes should
address that (and fix error stream handling along the way).

* fixes test setup and teardown to ensure exit handling is properly managed.
* fixes driver source to use the `exitHandler` and `errorSink` consistently

BUG=
==========

to

==========
CLI driver test re-enablement (#25001).

Another stab.  The rub, I *think*, to our failures are unexpected calls to
`exit()` on the bots (that are not reproducing locally).  These fixes should
address that (and fix error stream handling along the way).

* fixes test setup and teardown to ensure exit handling is properly managed.
* fixes driver source to use the `exitHandler` and `errorSink` consistently

BUG=
R=keertip@google.com, scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/5a57d6e8dcf24741dd8d099e971a189563b302f5
==========

[pquitslund, 2015-12-14 21:08:52]

Committed patchset #2 (id:20001) manually as
5a57d6e8dcf24741dd8d099e971a189563b302f5 (presubmit successful).