build: speed up karma run by passing in list of dist files that changed

[IgorMinar]

per discussion with @zzo...

This change causes the build system to write a log file into the tmp folder after each build.
This file contains command line arguments that tell karma about all the added/changed/removed files
from the last build. Karma can then use this list instead of doing internal globbing which can be
very expensive especially for hte dart builds that contain thousands of files.

Closes #2437

[IgorMinar]

This doesn't address the initial bootstrap latency which @zzo partly improved via more efficient globbing in the recent karma canary.

[tbosch]

Who can review this?

[IgorMinar]

maybe @alexeagle ?

[alexeagle]

what's with the 1100? should we at least log here if the length exceeds that?

[IgorMinar]

if it's more, we don't use the args at all and run karma without args which will work just fine, but will be slower.

the limit here is to avoid issues on windows where there is a limit for the length of a command send to the terminal.

[IgorMinar]

all add more docs

[alexeagle]

This works the same whether karma is running JS or Dart tests, right?
I don't know much about how karma will use this arg but I assume it will help :)

[IgorMinar]

yes. this works both for js and dart.

I've made all the other changes and merged this in.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}