Add optional message argument to assert statements in the VM.

Add optional message argument to assert statements in the VM.

Add flag --assert-message to control the feature.


Fixes issue #24215
BUG= http://dartbug.com/24215

This replaces Lasse’s CL  1307363005

patch from issue 1307363005 at patchset 140001 (http://crrev.com/1307363005#ps140001)

R=lrn@google.com

Committed: https://github.com/dart-lang/sdk/commit/67e83dd79d1e8b58ef5a73dcf7cfc2fb22b108b6

[hausner, 2016-12-09 00:59:37]

Description was changed from

==========
Add optional message argument to assert statements in the VM.

Add flag --assert-message to control the feature.


Fixes issue #24215
BUG= http://dartbug.com/24215

This replaces Lasse’s CL  1307363005

patch from issue 1307363005 at patchset 140001
(http://crrev.com/1307363005#ps140001)
==========

to

==========
Add optional message argument to assert statements in the VM.

Add flag --assert-message to control the feature.


Fixes issue #24215
BUG= http://dartbug.com/24215

This replaces Lasse’s CL  1307363005

patch from issue 1307363005 at patchset 140001
(http://crrev.com/1307363005#ps140001)
==========

[hausner, 2016-12-09 00:59:37]

hausner@google.com changed reviewers:
+ asiva@google.com, lrn@google.com

[Lasse Reichstein Nielsen, 2016-12-09 07:50:17]

LGTM if the test runs :)

We'll probably remove (or at least toggle) the flag real soon, since with this,
we have implementations for both VM, dart2js and analyzer. 
If you want to remove it now, feel free.

[hausner, 2016-12-09 17:26:02]

Description was changed from

==========
Add optional message argument to assert statements in the VM.

Add flag --assert-message to control the feature.


Fixes issue #24215
BUG= http://dartbug.com/24215

This replaces Lasse’s CL  1307363005

patch from issue 1307363005 at patchset 140001
(http://crrev.com/1307363005#ps140001)
==========

to

==========
Add optional message argument to assert statements in the VM.

Add flag --assert-message to control the feature.


Fixes issue #24215
BUG= http://dartbug.com/24215

This replaces Lasse’s CL  1307363005

patch from issue 1307363005 at patchset 140001
(http://crrev.com/1307363005#ps140001)

R=lrn@google.com

Committed:
https://github.com/dart-lang/sdk/commit/67e83dd79d1e8b58ef5a73dcf7cfc2fb22b108b6
==========

[hausner, 2016-12-09 17:26:03]

Committed patchset #1 (id:1) manually as
67e83dd79d1e8b58ef5a73dcf7cfc2fb22b108b6 (presubmit successful).