tint->dawn: Shuffle source tree in preperation of merging repos

docs/    -> docs/tint/
fuzzers/ -> src/tint/fuzzers/
samples/ -> src/tint/cmd/
src/     -> src/tint/
test/    -> test/tint/

BUG=tint:1418,tint:1433

Change-Id: Id2aa79f989aef3245b80ef4aa37a27ff16cd700b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/80482
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>

test/tint/array/assign_to_subexpr.wgsl

@@ -0,0 +1,27 @@
+type ArrayType = array<i32, 4>;
+
+struct S {
+  arr : array<i32, 4>;
+};
+
+fn foo() {
+  let src : ArrayType = ArrayType();
+
+  var dst : ArrayType;
+  var dst_struct : S;
+  var dst_array : array<ArrayType, 2>;
+  let dst_ptr : ptr<function, ArrayType> = &dst;
+  let dst_struct_ptr : ptr<function, S> = &dst_struct;
+  let dst_array_ptr : ptr<function, array<ArrayType, 2>> = &dst_array;
+
+  // Assign to struct.member.
+  dst_struct.arr = src;
+
+  // Assign to array[index].
+  dst_array[1] = src;
+
+  // Assign via pointers.
+  *dst_ptr = src;
+  (*dst_struct_ptr).arr = src;
+  (*dst_array_ptr)[0] = src;
+}