build(vitest): try reverting e2e vitest pool to v1 config to fix new flakiness (#7210)

* build(vitest): remove unneeded e2e vitest config

* build(vitest): try reverting e2e vitest pool to v1 config

* build(vitest): move `deps.external` to new location

* build(vitest): remove unnecessary config

Author: serhalp

vitest.config.ts

@@ -14,10 +14,6 @@ export default defineConfig({
         ],
       },
     },
-    deps: {
-      external: ['**/fixtures/**', '**/node_modules/**'],
-      interopDefault: false,
-    },
     snapshotFormat: {
       escapeString: true,
     },

vitest.e2e.config.ts

@@ -4,9 +4,13 @@ export default defineConfig({
   test: {
     include: ['e2e/**/*.e2e.[jt]s'],
     testTimeout: 600_000,
-    deps: {
-      external: ['**/fixtures/**', '**/node_modules/**'],
-      interopDefault: false,
+    // Pin to vitest@1 behavior: https://vitest.dev/guide/migration.html#default-pool-is-forks.
+    // TODO(serhalp) Remove this and fix flaky hanging e2e tests on Windows.
+    pool: 'threads',
+    poolOptions: {
+      threads: {
+        singleThread: true,
+      },
     },
   },
 })