Guard early direct-file staging paths

wasm-port/tests/browser/interp_smoke.html

@@ -6288,6 +6288,20 @@
         "do-while-break",
         "bug.ngc",
       );
+      const doWhileBreakNgcFiles = [
+        "bug.ngc",
+        "test.ngc",
+      ];
+      if (doWhileBreakNgcFiles.length !== 2 || new Set(doWhileBreakNgcFiles).size !== doWhileBreakNgcFiles.length) {
+        throw new Error("browser_interp_do_while_break_fixture_coverage: list drift");
+      }
+      const doWhileBreakStagedNgcFiles = [
+        doWhileBreakBugPath,
+        doWhileBreakPath,
+      ].map((path) => path.replace("/work/browser-interp/do-while-break/", ""));
+      if (doWhileBreakStagedNgcFiles.join(",") !== doWhileBreakNgcFiles.join(",")) {
+        throw new Error("browser_interp_do_while_break_staging_manifest: list drift");
+      }
       verifyExpectedOutput(
         "browser_interp_do_while_break_bug",
         interp.runFile(doWhileBreakBugPath),
@@ -6341,6 +6355,18 @@
       );
 
       const existsPath = await writeInterpRegressionFile(interp, "exists", "test.ngc");
+      const existsNgcFiles = [
+        "test.ngc",
+      ];
+      if (existsNgcFiles.length !== 1 || new Set(existsNgcFiles).size !== existsNgcFiles.length) {
+        throw new Error("browser_interp_exists_fixture_coverage: list drift");
+      }
+      const existsStagedNgcFiles = [
+        existsPath,
+      ].map((path) => path.replace("/work/browser-interp/exists/", ""));
+      if (existsStagedNgcFiles.join(",") !== existsNgcFiles.join(",")) {
+        throw new Error("browser_interp_exists_staging_manifest: list drift");
+      }
       verifyExpectedOutput(
         "browser_interp_exists",
         interp.runFile(existsPath),
@@ -6360,6 +6386,18 @@
         "return-value",
         "test.ngc",
       );
+      const returnValueNgcFiles = [
+        "test.ngc",
+      ];
+      if (returnValueNgcFiles.length !== 1 || new Set(returnValueNgcFiles).size !== returnValueNgcFiles.length) {
+        throw new Error("browser_interp_return_value_fixture_coverage: list drift");
+      }
+      const returnValueStagedNgcFiles = [
+        returnValuePath,
+      ].map((path) => path.replace("/work/browser-interp/return-value/", ""));
+      if (returnValueStagedNgcFiles.join(",") !== returnValueNgcFiles.join(",")) {
+        throw new Error("browser_interp_return_value_staging_manifest: list drift");
+      }
       verifyExpectedOutput(
         "browser_interp_return_value",
         interp.runFile(returnValuePath),