Native bindings to the QCOM_shader_framebuffer_fetch_noncoherent extension.

Existing extensions such as EXT_shader_framebuffer_fetch and ARM_shader_framebuffer_fetch_depth_stencil allow fragment shaders to read existing framebuffer color or depth/stencil data as input. This extension adds support for reading those same inputs with relaxed coherency requirements. This mode can avoid expensive per-primitive flushes of the pixel pipeline and may offer performance improvements in some implementations.

When the relaxed coherency mode is enabled, reads of the framebuffer data by the fragment shader will guarantee defined results only if each sample is touched no more than once in any single rendering pass. The command FramebufferFetchBarrierQCOM is provided to indicate a boundary between passes.