[WGSL] Add support for call expressions with packed types

[tadeuzagallo]

e553d77

[WGSL] Add support for call expressions with packed types
https://bugs.webkit.org/show_bug.cgi?id=258029
rdar://110712618

Reviewed by Mike Wyrzykowski.

Expand the global variable rewriter to support call expressions with packed values.
Calls work by unpacking all arguments, and their result is always unpacked.

* Source/WebGPU/WGSL/GlobalVariableRewriter.cpp:
(WGSL::RewriteGlobalVariables::pack):
(WGSL::RewriteGlobalVariables::getPacking):
* Source/WebGPU/WGSL/tests/valid/packing.wgsl:

Canonical link: https://commits.webkit.org/265151@main

be5eef4

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt		✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash be5eef4)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt		✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[mwyrzykowski]

Test failures appear unrelated

[webkit-commit-queue]

Committed 265151@main (e553d77): https://commits.webkit.org/265151@main

Reviewed commits have been landed. Closing PR #14926 and removing active labels.