vcpkg: Figure out how to optimize pixman in debug build

[Ghabry]

The debug version of pixman is super slow and gives 0 FPS in many situations.

We can't simply force the pixman release library when building Player because it uses LIBCMT instead of LIBCMTd which gives warning during linking and can have unexpected side effects because of mixed up C library functions.

In my crazy powershell script this was supported via a DebugFast flag btw (had high priority at this time because I was programming on Windows and this was really frustrating)