tests: Replace FAIL() macro in ErrorMonitor

Use of the gtest FAIL() macro within VerifyFound() and
VerifyNotFound() caused it to abort after first message,
and skipped the Reset() call. (FAIL macro decodes to return).
Replaced with ADD_FAILURE() which records the failure
but doesn't abort the reporting loop.

Change-Id: I71fff87609e093e96d1186f24338fe04f3346b66
diff --git a/tests/layer_validation_tests.cpp b/tests/layer_validation_tests.cpp
index c05603f..9e48f45 100644
--- a/tests/layer_validation_tests.cpp
+++ b/tests/layer_validation_tests.cpp
@@ -253,10 +253,10 @@
         if (!AllDesiredMsgsFound()) {
             DumpFailureMsgs();
             for (auto desired_msg : desired_message_strings_) {
-                FAIL() << "Did not receive expected error '" << desired_msg << "'";
+                ADD_FAILURE() << "Did not receive expected error '" << desired_msg << "'";
             }
             for (auto desired_id : desired_message_ids_) {
-                FAIL() << "Did not receive expected error '" << desired_id << "'";
+                ADD_FAILURE() << "Did not receive expected error ENUM '" << desired_id << "'";
             }
         }
         Reset();
@@ -267,7 +267,7 @@
         if (AnyDesiredMsgFound()) {
             DumpFailureMsgs();
             for (auto msg : failure_message_strings_) {
-                FAIL() << "Expected to succeed but got error: " << msg;
+                ADD_FAILURE() << "Expected to succeed but got error: " << msg;
             }
         }
         Reset();
@@ -5397,7 +5397,7 @@
     m_errorMonitor->VerifyFound();
 
     // Try again once the queue is idle - should succeed w/o error
-    // TODO - thought the particular error above doesn't re-occur, there are other 'unexpecteds' still to clean up
+    // TODO - though the particular error above doesn't re-occur, there are other 'unexpecteds' still to clean up
     vkQueueWaitIdle(m_device->m_queue);
     vkFreeDescriptorSets(m_device->device(), ds_pool, 1, &descriptorSet);