Fix reporting of errors during test setup (#51704)

Summary:
Pull Request resolved: #51704

Changelog: [internal]

If you create a Fantom test that throws an error during its setup (not during the execution of specific tests), Fantom fails with an error saying there are no tests defined, which isn't useful.

This fixes the problem and shows where the error in the test setup happened exactly.

Reviewed By: javache

Differential Revision: D75689283

fbshipit-source-id: 54dd2382868dda0d284f46743ed94ba94aa3afdc

Author: rubennorte

packages/react-native-fantom/runtime/setup.js

@@ -190,18 +190,13 @@ global.jest = {
 
 global.expect = expect;
 
+let testSetupError: ?Error;
+
 function runWithGuard(fn: () => void) {
   try {
     fn();
   } catch (error) {
-    let reportedError =
-      error instanceof Error ? error : new Error(String(error));
-    reportTestSuiteResult({
-      error: {
-        message: reportedError.message,
-        stack: reportedError.stack,
-      },
-    });
+    testSetupError = error instanceof Error ? error : new Error(String(error));
   }
 }
 
@@ -400,9 +395,18 @@ function validateEmptyMessageQueue(): void {
 }
 
 global.$$RunTests$$ = () => {
-  reportTestSuiteResult({
-    testResults: runSuite(currentContext),
-  });
+  if (testSetupError != null) {
+    reportTestSuiteResult({
+      error: {
+        message: testSetupError.message,
+        stack: testSetupError.stack,
+      },
+    });
+  } else {
+    reportTestSuiteResult({
+      testResults: runSuite(currentContext),
+    });
+  }
 };
 
 export function registerTest(