tdf#82775: Don't prematurely dispose single-instance services

...that happen to be requested concurrently from multiple threads

Change-Id: Icecfb0b8d88c9123064689643eddf90a99d3b1b8

cppuhelper/source/component_context.cxx

@@ -620,7 +620,9 @@ Any ComponentContext::lookupMap( OUString const & rName )
             ret = pEntry->value;
     }
     guard.clear();
-    try_dispose( xInstance );
+    if (ret != xInstance) {
+        try_dispose( xInstance );
+    }
     return ret;
 }