Fix so that you can run presubmit.py in Windows.
presubmit.py tried to execute cpplint.py directly, but in Windows it's the shell that connects that to the python binary so the execution (subprocess.Popen) needs to be told how to find python. An alternative would be to call subprocess.Popen with shell=True but this is less dangerous.

Review URL: https://chromiumcodereview.appspot.com/13849008

Patch from Daniel Bratell <bratell@opera.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14263 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Calling a generator function returns a generator object

* src/heap.h:
* src/heap.cc:
* src/objects-debug.cc:
* src/objects-inl.h:
* src/objects-printer.cc:
* src/objects-visiting.cc:
* src/objects.cc:
* src/objects.h: Define a new object type, JSGeneratorObject.

* src/factory.h:
* src/factory.cc (NewFunctionFromSharedFunctionInfo): Generator function
  inital maps construct the new JS_GENERATOR_OBJECT_TYPE objects, not
  generic JSObjects.

* src/runtime.h:
* src/runtime.cc (Runtime_CreateJSGeneratorObject):
* src/arm/full-codegen-arm.cc (Generate):
* src/ia32/full-codegen-ia32.cc (Generate):
* src/x64/full-codegen-x64.cc (Generate): Before visiting generator
  bodies, arrange to construct and return a generator object.

* test/mjsunit/harmony/generators-objects.js: Add tests for the
  properties and prototype of generator objects.

BUG=v8:2355
TEST=mjsunit/harmony/generators-objects

Review URL: https://codereview.chromium.org/13542002

Patch from Andy Wingo <wingo@igalia.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14264 ce2b1a6d-e550-0410-aec6-3dcde31c8c00