mesa: check that internalformat of CopyTexImage*D is not 1, 2, 3, 4
mesa: check that internalformat of CopyTexImage*D is not 1, 2, 3, 4

The piglit copyteximage check has recently been augmented to test this, but
apparently it hasn't been fixed in Mesa so far.

This language also already appears in the OpenGL 2.1 spec (Ian).

Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler