[3.13] Add a --rerun option to the iOS testbed. (GH-122992) (#122993)

Enable --rerun when running tests on iOS.
(cherry picked from commit ce39d3c6bd)

Co-authored-by: Russell Keith-Magee <russell@keith-magee.com>

iOS/testbed/iOSTestbedTests/iOSTestbedTests.m

@@ -15,6 +15,7 @@
     const char *argv[] = {
         "iOSTestbed", // argv[0] is the process that is running.
         "-uall",  // Enable all resources
+        "--rerun",  // Re-run failed tests in verbose mode
         "-W",  // Display test output on failure
         // To run a subset of tests, add the test names below; e.g.,
         // "test_os",