src: check uv_async_init() return value

Pointed out by Coverity.

PR-URL: #7374
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

Author: bnoordhuis

src/node.cc

@@ -3857,9 +3857,9 @@ void Init(int* argc,
 
   // init async debug messages dispatching
   // Main thread uses uv_default_loop
-  uv_async_init(uv_default_loop(),
-                &dispatch_debug_messages_async,
-                DispatchDebugMessagesAsyncCallback);
+  CHECK_EQ(0, uv_async_init(uv_default_loop(),
+                            &dispatch_debug_messages_async,
+                            DispatchDebugMessagesAsyncCallback));
   uv_unref(reinterpret_cast<uv_handle_t*>(&dispatch_debug_messages_async));
 
 #if defined(NODE_V8_OPTIONS)

src/node_win32_etw_provider.cc

@@ -155,9 +155,9 @@ void init_etw() {
     event_write = (EventWriteFunc)GetProcAddress(advapi, "EventWrite");
 
     // create async object used to invoke main thread from callback
-    uv_async_init(uv_default_loop(),
-                  &dispatch_etw_events_change_async,
-                  etw_events_change_async);
+    CHECK_EQ(0, uv_async_init(uv_default_loop(),
+                              &dispatch_etw_events_change_async,
+                              etw_events_change_async));
     uv_unref(reinterpret_cast<uv_handle_t*>(&dispatch_etw_events_change_async));
 
     if (event_register) {