vm: Avoid list allocation for empty map literals

vm: Avoid list allocation for empty map literals.

This reduces the number of _List(0) allocations in a dart2js compile by ~3%.

R=hausner@google.com

Committed: https://github.com/dart-lang/sdk/commit/30f3df8f2637ba91def56924a8b7e579e94a51e4

[sra1, 2016-03-19 23:37:19]

Description was changed from

==========
vm: Avoid list allocation for empty map literals
==========

to

==========
vm: Avoid list allocation for empty map literals.

This reduces the number of _List(0) allocations in a dart2js compile by ~3%.
==========

[sra1, 2016-03-19 23:37:20]

sra@google.com changed reviewers:
+ asiva@google.com

[sra1, 2016-03-19 23:38:02]

Patchset #1 (id:1) has been deleted

[sra1, 2016-03-21 19:44:19]

sra@google.com changed reviewers:
+ hausner@google.com
- asiva@google.com

[sra1, 2016-03-21 19:44:44]

Changing reviewer to hausner

[hausner, 2016-03-21 20:08:29]

lgtm

[sra1, 2016-03-22 17:34:28]

Description was changed from

==========
vm: Avoid list allocation for empty map literals.

This reduces the number of _List(0) allocations in a dart2js compile by ~3%.
==========

to

==========
vm: Avoid list allocation for empty map literals.

This reduces the number of _List(0) allocations in a dart2js compile by ~3%.

R=hausner@google.com

Committed:
https://github.com/dart-lang/sdk/commit/30f3df8f2637ba91def56924a8b7e579e94a51e4
==========

[sra1, 2016-03-22 17:34:29]

Committed patchset #1 (id:20001) manually as
30f3df8f2637ba91def56924a8b7e579e94a51e4 (presubmit successful).