cmake: test for EGL and GLES on Windows, avoid EGL test on MSVC

[madebr]

For MSVC platforms, SDL3/SDL_egl.h has the following conditional to avoid including a system EGL/egl.h: https://github.com/libsdl-org/SDL/blob/dd955332a2795d8b60731b1864eeab44341baf8d/include/SDL3/SDL_egl.h#L28

Perhaps this should include Windows platforms?

If a CMake test is preferred, we were only detecting egl.h for the unix platforms. This pr adds a test for the Windows platform. When using MSVC, it avoids a check for <EGL/egl.h> and <EGL/eglext.h> includes.

It adds checks for

• <GLES/gl.h> and <GLES/glext.h> includes in CheckOpenGLES for SDL_VIDEO_OPENGL_ES
• <GLES2/gl2.h> and <GLES2/gl2ext.h> includes in CheckOpenGLES for SDL_VIDEO_OPENGL_ES2

The MSVC behavior should be the same, but please review.

Existing Issue(s)

Fixes https://github.com/libsdl-org/SDL/issues/11216