Remove conflicting checks in OpenXrTestHelper::EndSession

xrEndSession should only be called in the XR_ERROR_SESSION_NOT_STOPPING
per the OpenXr spec, so checking for the running state isn't necessary.

Bug: 1116111
Change-Id: I089846d868441d8cd2d6d9bd82534859966d8772
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2357511Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Patrick To <patrto@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#798277}

device/vr/openxr/test/openxr_test_helper.cc

@@ -358,8 +358,8 @@ XrResult OpenXrTestHelper::BeginSession() {
 }
 
 XrResult OpenXrTestHelper::EndSession() {
-  RETURN_IF_FALSE(IsSessionRunning(), XR_ERROR_SESSION_NOT_RUNNING,
-                  "EndSession session is not running");
+  // Per OpenXR 1.0 spec: "An application can only call xrEndSession when the
+  // session is in the XR_SESSION_STATE_STOPPING state"
   RETURN_IF(session_state_ != XR_SESSION_STATE_STOPPING,
             XR_ERROR_SESSION_NOT_STOPPING,
             "Session state is not XR_ERROR_SESSION_NOT_STOPPING");