GPU: Add workarounds for buggy glBlitFramebuffer function on macOS + Radeon

When calling glBlitFramebuffer on most (if not all) mac that have a GPU
from the Radeon Pro series, the data is not properly copied and only a
subset of the pixels are correctly copied.

This only happens when blitting the depth buffer if the depth buffer is
GL_DEPTH24_STENCIL8.

Changing the depth buffer format to GPU_DEPTH32F_STENCIL8 fixes the issue
but only works if blitting the depth componnent. The stencil componnent
still provoke issues when being copied.

source/blender/gpu/GPU_extensions.h

@@ -52,6 +52,7 @@ int GPU_max_ubo_size(void);
 int GPU_color_depth(void);
 void GPU_get_dfdy_factors(float fac[2]);
 bool GPU_mip_render_workaround(void);
+bool GPU_depth_blitting_workaround(void);
 
 bool GPU_mem_stats_supported(void);
 void GPU_mem_stats_get(int *totalmem, int *freemem);