Fixed memory leaks in runtime/bin/dartutils.cc

Fixed memory leaks in runtime/bin/dartutils.cc

R=asiva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25608

[kustermann, 2013-07-29 21:38:48]

This CL fixes a memory leak in the script loading code.
(All source files will be read again for every call to 'spawnFunction()' --
meaning that large applications that do a lot of 'spawnFunction()' calls leak a
lot of memory)

[kustermann, 2013-07-29 21:41:31]

As a side note: I was a bit surprised when I saw this code. It's not exactly
pretty when nested functions malloc() memory and outer functions have to free it
(leaks can happen easily). Why not using zone-allocated memory (or using refptr
...)?

[siva, 2013-07-29 23:39:06]

LGTM

The Zone data structures are not available here in the bin
directory, we would have to have yet another implementation
of Zone for files in this directory.

[kustermann, 2013-07-30 07:13:37]

Committed patchset #1 manually as r25608 (presubmit successful).

[kustermann, 2013-07-30 07:40:04]

Thank you.