Remove heap settings from pub scripts for SDK too.

Remove heap settings from pub scripts for SDK too.

r43821 only does it for the scripts used to run pub from within the source repo.

Also add support to the Windows shell script for passing VM flags to pub similar to
what dart2js and the bash pub scripts allow.

BUG=https://code.google.com/p/dart/issues/detail?id=22461
R=ahe@google.com, nweiz@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43925

[Bob Nystrom, 2015-02-20 18:10:16]

rnystrom@google.com changed reviewers:
+ ahe@google.com, nweiz@google.com

[Bob Nystrom, 2015-02-20 18:10:17]

I added you, Peter, because I think you're one of the few people on the team
with any batch file experience. :) These changes are copied from dart2js's batch
file, so I *think* they're correct, but I'd appreciate another pair of eyes.

Thanks!

[ahe, 2015-02-20 18:34:25]

I can see you copied this code from dart2js.bat, and that was tweaked by Johnni
(who uses Windows as his primary workstation) to something written by Alexander
that know more about this stuff than anyone I know. So LGTM from me!

[nweiz, 2015-02-20 19:03:48]

lgtm

Do we still need two separate scripts for these now that we don't do async/await
compilation anymore?

[Bob Nystrom, 2015-02-20 20:15:04]

On 2015/02/20 19:03:48, nweiz wrote:
> lgtm
> 
> Do we still need two separate scripts for these now that we don't do
async/await
> compilation anymore?

Yeah, I think it's still useful. There's a bunch of directory munging that we do
when running from the repo to find the build directory and stuff. I like not
having that in the loop when normal end users are running from the SDK. dart2js
and the analyzer now have separate SDK and repo scripts too.

- bob

[Bob Nystrom, 2015-02-20 20:15:35]

Committed patchset #1 (id:1) manually as 43925 (presubmit successful).