reference.rc test: Don't run preprocessor to avoid dependence on clang

The preprocessor is not necessary for the test to pass, so this avoidance just means that the test doesn't require the system to have a clang installation available.

test/reference.zig

@@ -39,7 +39,7 @@ test "reference.rc" {
     var result = try utils.getResinatorResult(std.testing.allocator, reference_rc, .{
         .cwd = tmp.dir,
         .cwd_path = tmp_path,
-        .run_preprocessor = true,
+        .run_preprocessor = false,
     });
     defer result.deinit(std.testing.allocator);