cmNinjaTargetGenerator: Use short path for cmcldeps.exe

This commit fixes an issue with quote-escaped executable/command paths not playing will with Ninja when using MSVC and compiling RC files. Specifically I've used cmSystemTools::GetShortPath to transform the cmcldeps.exe path to the short format where the path is used within cmNinjaTargerGenerator.cxx.

I'm unsure if the fix proposed in this merge request is the best fit for the CMake codebase, as I'm pretty unfamiliar with it. Please let me know if I my solution is subpar.

I've documented the problem in this forum post.

Please let me know if I should create an issue to track this bug.