Guard m98m99 mixed-sub-style staging

wasm-port/tests/browser/interp_smoke.html

@@ -7992,7 +7992,22 @@
         ].join("\n"),
       );
 
-      const m98m99MixedSubStylePaths = [];
+      const m98m99MixedSubStyleFiles = [
+        "O...-called-with-O..._call.ngc",
+        "O...-ended-with-O..._endsub.ngc",
+        "O...-sub-called-with-M98.ngc",
+        "O...-sub-ended-with-M99.ngc",
+      ];
+      const m98m99MixedSubStyleDir = await writeInterpRegressionFiles(
+        interp,
+        "m98m99/06-error-mixed-sub-styles",
+        m98m99MixedSubStyleFiles,
+      );
+      assertInterpRegressionStaging(
+        "m98m99/06-error-mixed-sub-styles",
+        m98m99MixedSubStyleFiles,
+        m98m99MixedSubStyleDir,
+      );
       for (const mixedSubStyleFixture of [
         {
           name: "called_with_o_call",
@@ -8037,12 +8052,7 @@
           print: "X FANUC",
         },
       ]) {
-        const mixedSubStylePath = await writeInterpRegressionFile(
-          interp,
-          "m98m99/06-error-mixed-sub-styles",
-          mixedSubStyleFixture.file,
-        );
-        m98m99MixedSubStylePaths.push(mixedSubStylePath);
+        const mixedSubStylePath = `${m98m99MixedSubStyleDir}/${mixedSubStyleFixture.file}`;
         const mixedSubStyleRun = runWithCapturedPrints(() =>
           interp.runFile(mixedSubStylePath),
         );
@@ -8069,12 +8079,6 @@
           );
         }
       }
-      const m98m99MixedStagedNgcFiles = [
-        ...m98m99MixedSubStylePaths,
-      ].map((path) => path.replace("/work/browser-interp/m98m99/", ""));
-      if (m98m99MixedStagedNgcFiles.join(",") !== m98m99RegressionFiles.slice(5, 9).join(",")) {
-        throw new Error("browser_interp_m98m99_mixed_staging_manifest: list drift");
-      }
 
       const m98m99NestedSubsPath = await writeInterpRegressionFile(
         interp,