Normalize path before requesting list of targets (ninja)
Normalize path before requesting list of targets (ninja)

Fixes test/sibling/ on Windows ninja. In lieu of http://chromiumcodereview.appspot.com/9406035/

When loading build files and the targets out of them gyp.input.Load normpaths the build_file part of a build_file.gyp#target in the targets list (because they're used internally as keys in a dict). However, the list of build files passed to the generator are not normalized (because they're just filenames, not dict keys).

Build files are specified in / format in gyp files, so on POSIX there's no difference anyway.

In the ninja generator when we use common.AllTargets to extract all the targets that apply a build file. AllTargets does a simple substring compare (via common.BuildFile), and since the build files that we pass in are the file names, we need to normpath them first so that they match the normalized dict keys that input.Load used.

Alternatively, we could change common.BuildFile to normpath, however that might have a more broad performance impact as it's more heavily used than this more local change.
Review URL: https://chromiumcodereview.appspot.com/9433024

csulmone/gyp,csulmone/gyp,csulmone/gyp,csulmone/gyp