testing: fix multiple race conditions in simulated time tests

Fixes #12480
Fixes #10568

Signed-off-by: Matt Klein <mklein@lyft.com>

test/integration/autonomous_upstream.cc

@@ -34,16 +34,19 @@ AutonomousStream::~AutonomousStream() {
 
 // By default, automatically send a response when the request is complete.
 void AutonomousStream::setEndStream(bool end_stream) {
-  FakeStream::setEndStream(end_stream);
+  {
+    absl::MutexLock lock(&lock_);
+    FakeStream::setEndStream(end_stream);
+  }
   if (end_stream) {
     sendResponse();
   }
 }
 
 // Check all the special headers and send a customized response based on them.
 void AutonomousStream::sendResponse() {
-  Http::TestResponseHeaderMapImpl headers(*headers_);
-  upstream_.setLastRequestHeaders(*headers_);
+  Http::TestResponseHeaderMapImpl headers(this->headers());
+  upstream_.setLastRequestHeaders(this->headers());
 
   int32_t request_body_length = -1;
   HeaderToInt(EXPECT_REQUEST_SIZE_BYTES, request_body_length, headers);

test/integration/cx_limit_integration_test.cc

@@ -47,7 +47,7 @@ class ConnectionLimitIntegrationTest : public testing::TestWithParam<Network::Ad
       if (Network::AcceptedSocketImpl::acceptedSocketCount() == expected_connections) {
         return AssertionSuccess();
       }
-      timeSystem().advanceTimeWait(std::chrono::milliseconds(500));
+      timeSystem().advanceTimeWait(std::chrono::milliseconds(500), true);
     }
     if (Network::AcceptedSocketImpl::acceptedSocketCount() == expected_connections) {
       return AssertionSuccess();