Roll src/third_party/dart 28c4c6c156e5..114752421dca (17 commits)

[skia-flutter-autoroll]

https://dart.googlesource.com/sdk.git/+log/28c4c6c156e5..114752421dca

git log 28c4c6c..1147524 --date=short --first-parent --format='%ad %ae %s'
2020-04-08 srujzs@google.com [dart:html] Remove multitest usage in some js tests
2020-04-08 jcollins@google.com Switch migration to the isolate client.
2020-04-08 jwren@google.com Follow up on https://dart-review.googlesource.com/c/sdk/+/142705 to fix the assertion in the new completions in FieldDeclarations
2020-04-08 rmacnak@google.com [vm, service] Explicitly mention that timeline events are not ordered.
2020-04-08 rnystrom@google.com Migrate language_2/factory to NNBD.
2020-04-08 rnystrom@google.com Migrate language_2/field to NNBD.
2020-04-08 nshahan@google.com [ddc] Run modular test suite in weak mode
2020-04-08 sra@google.com [js_runtime] Streamline String.fromCharCodes
2020-04-08 joshualitt@google.com [dart2js] Always compute platform binaries.
2020-04-08 scheglov@google.com Issue 41399. Check for 'dynamic' and 'Never' when verifying EXPORT_LEGACY_SYMBOL.
2020-04-08 scheglov@google.com Make all named parameters of BestPracticesVerifier required.
2020-04-08 brianwilkerson@google.com Update code_metrics to support running it over a corpus
2020-04-08 scheglov@google.com Support for analysis options in FileResolver.
2020-04-08 scheglov@google.com Remove the special case for getGreatestLowerBound() in inference.
2020-04-08 scheglov@google.com Don't report MISSING_DEFAULT_VALUE_FOR_PARAMETE for external factory constructors.
2020-04-08 kustermann@google.com Revert "Reland "[vm, gc] Parallel scavenge.""
2020-04-08 kustermann@google.com [vm/compiler] Use pc-relative calls to various stubs by moving the stubs to the isolate

Created with:
gclient setdep -r src/third_party/dart@114752421dca

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: dart-vm-team@google.com

[a-siva]

The tests appear to have run successfully but PR still shows pending, force merging it to keep the rolls progressing.