ICU-3718 Don't crash on slow machines

X-SVN-Rev: 15497

icu4c/source/test/intltest/tsmthred.cpp

@@ -1514,10 +1514,18 @@ void MultithreadTest::TestString()
     }
 
 cleanupAndReturn:
+    if (terrs == 0) {
+        /*
+        Don't clean up if there are errors. This prevents crashes if the
+        threads are still running and using this data. This will only happen
+        if there is an error with the test, ICU, or the machine is too slow.
+        It's better to leak than crash.
+        */
         for(j = 0; j < kStringThreadThreads; j++) {
             delete tests[j];
         }
-    return;
+        delete testString;
+    }
 }