- Allow an isolate to be started in paused state.

R=asiva@google.com

Review URL: https://codereview.chromium.org//822803003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42576 260f80e4-7a28-3924-810f-c04153c831b5
Interrupt isolates immediately

After requesting the interrupt, send a null message to the isolate
to ensure the isolate runs and detects the interrupt request immediately.

Fixes issue 21047.

R=iposva@google.com

Review URL: https://codereview.chromium.org//789243003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42577 260f80e4-7a28-3924-810f-c04153c831b5
Too much const kills the build

Review URL: https://codereview.chromium.org//829993003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42578 260f80e4-7a28-3924-810f-c04153c831b5