[WGSL] Atomics should return the size and alignment of their underlying type
<rdar://problem/116544747>
Pull request: https://github.com/WebKit/WebKit/pull/18724
Committed 268953@main (325c996d6dc3): <https://commits.webkit.org/268953@main> Reviewed commits have been landed. Closing PR #18724 and removing active labels.