Ninja: fix ARMClang paths for Windows
We need to escape paths for ARMClang on Windows, see the referenced issue for more details.
Tested with Mbed OS master branch, ARMClang 6.14 and blinky example. I modified our CMake to force response files for Ninja generator. Without this fix, it fails to build (it can't find header files, paths are incorrectly escaped). I applied this fix, and was able to build it without any errors on Windows platform.
Fixes: #21093 (closed)