cleanup: Refactor tests to use ast::Builder helpers

Change-Id: I5bf1dac217c9c6192c0637d98c4a38196d41cbe8
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/36382
Commit-Queue: Ben Clayton <bclayton@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
diff --git a/src/writer/msl/generator_impl_import_test.cc b/src/writer/msl/generator_impl_import_test.cc
index ef9132d..b7d97d6 100644
--- a/src/writer/msl/generator_impl_import_test.cc
+++ b/src/writer/msl/generator_impl_import_test.cc
@@ -117,8 +117,8 @@
 TEST_P(MslImportData_DualParam_VectorTest, FloatVector) {
   auto param = GetParam();
 
-  auto* expr = Call(param.name, Construct(ty.vec3<f32>(), 1.f, 2.f, 3.f),
-                    Construct(ty.vec3<f32>(), 4.f, 5.f, 6.f));
+  auto* expr =
+      Call(param.name, vec3<f32>(1.f, 2.f, 3.f), vec3<f32>(4.f, 5.f, 6.f));
   ASSERT_TRUE(td.DetermineResultType(expr)) << td.error();
   ASSERT_TRUE(gen.EmitCall(expr)) << gen.error();
   EXPECT_EQ(gen.result(), std::string("metal::") + param.msl_name +
@@ -178,10 +178,7 @@
                                          MslImportData{"clamp", "clamp"}));
 
 TEST_F(MslGeneratorImplTest, MslImportData_Determinant) {
-  ast::type::F32 f32;
-  ast::type::Matrix mat(&f32, 3, 3);
-
-  auto* var = Var("var", ast::StorageClass::kFunction, &mat);
+  auto* var = Var("var", ast::StorageClass::kFunction, ty.mat3x3<f32>());
   mod->AddGlobalVariable(var);
 
   auto* expr = Call("determinant", "var");