[ir] Remove unused worklist

Change-Id: Ie4cb7ebaa4f0fb6a1eb44270c6b9b09151712b27
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/186562
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: James Price <jrprice@google.com>
diff --git a/src/tint/lang/core/ir/transform/vectorize_scalar_matrix_constructors.cc b/src/tint/lang/core/ir/transform/vectorize_scalar_matrix_constructors.cc
index b8c7703..37bdb03 100644
--- a/src/tint/lang/core/ir/transform/vectorize_scalar_matrix_constructors.cc
+++ b/src/tint/lang/core/ir/transform/vectorize_scalar_matrix_constructors.cc
@@ -54,7 +54,6 @@
     /// Process the module.
     void Process() {
         // Find and replace matrix constructors that take scalar operands.
-        Vector<Construct*, 8> worklist;
         for (auto inst : ir.Instructions()) {
             if (auto* construct = inst->As<Construct>()) {
                 if (construct->Result(0)->Type()->As<type::Matrix>()) {