ProgramBuilder: Remove storage parameter from [Global]Const()

Storage classes are unused for constants.

Also trim extra arguments to these variable constructor functions that are already defaulted to the same value.

Change-Id: Ia0b44364de000bfb8799de15827ce08fcce5f5be
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/41541
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Reviewed-by: David Neto <dneto@google.com>

src/inspector/inspector_test.cc

@@ -175,7 +175,7 @@ class InspectorHelper : public ProgramBuilder {
       constructor =
           create<ast::ScalarConstructorExpression>(MakeLiteral(type, val));
     }
-    GlobalConst(name, type, ast::StorageClass::kNone, constructor,
+    GlobalConst(name, type, constructor,
                 ast::VariableDecorationList{
                     create<ast::ConstantIdDecoration>(id),
                 });
@@ -319,11 +319,11 @@ class InspectorHelper : public ProgramBuilder {
                   ast::StorageClass storage_class,
                   uint32_t group,
                   uint32_t binding) {
-    GlobalConst(name, type, storage_class, nullptr,
-                ast::VariableDecorationList{
-                    create<ast::BindingDecoration>(binding),
-                    create<ast::GroupDecoration>(group),
-                });
+    Global(name, type, storage_class, nullptr,
+           ast::VariableDecorationList{
+               create<ast::BindingDecoration>(binding),
+               create<ast::GroupDecoration>(group),
+           });
   }
 
   /// Adds an uniform buffer variable to the program