This is a follow-up from #1580 (comment)
Currently, WGSL spec only describes the clamping behavior. Instead, it should follow WebGPU group decision to allow any of the following behaviors:

• discard the whole draw call
• behave like RBA, which means reading can return anything within the buffer (not within the array), or zeroes, or other stuff
• behave like D3D, which means reading always returns zeroes, and writing is ignored