[WGSL] Add metal tests to array functions

https://bugs.webkit.org/show_bug.cgi?id=267225
rdar://120645966

Reviewed by Mike Wyrzykowski.

Run the arrayLength test (the only function in the built-in array functions section)
through the metal compiler.

* Source/WebGPU/WGSL/tests/valid/overload.wgsl:

Canonical link: https://commits.webkit.org/272811@main

Source/WebGPU/WGSL/tests/valid/overload.wgsl

@@ -1647,10 +1647,12 @@ fn testSelect()
 
 // 16.4. Array Built-in Functions
 
-var<storage, read> a1: array<i32>;
-var<storage, read_write> a2: array<i32>;
+@group(4) @binding(0) var<storage, read> a1: array<i32>;
+@group(4) @binding(1) var<storage, read_write> a2: array<i32>;
 
 // 16.4.1.
+// RUN: %metal-compile testArrayLength
+@compute @workgroup_size(1)
 fn testArrayLength()
 {
     // [T].(Ptr[Storage, Array[T], Read]) => U32,