Add events for markers in GL/D3D11 so they don't mess up replay

* If a marker was the very first event, we want to be able to fetch it
  so the replay isn't off-by-one after that.

renderdoc/driver/d3d11/d3d11_context.cpp

@@ -889,11 +889,9 @@ bool WrappedID3D11DeviceContext::ProcessChunk(ReadSerialiser &ser, D3D11Chunk ch
       if(m_DrawcallStack.size() > 1)
         m_DrawcallStack.pop_back();
     }
-    else
-    {
-      if(!m_AddedDrawcall)
-        AddEvent();
-    }
+
+    if(!m_AddedDrawcall)
+      AddEvent();
   }
 
   m_AddedDrawcall = false;

renderdoc/driver/gl/gl_driver.cpp

@@ -4105,12 +4105,11 @@ bool WrappedOpenGL::ContextProcessChunk(ReadSerialiser &ser, GLChunk chunk)
           m_DrawcallStack.pop_back();
         break;
       }
-      default:
-      {
-        if(!m_AddedDrawcall)
-          AddEvent();
-      }
+      default: break;
     }
+
+    if(!m_AddedDrawcall)
+      AddEvent();
   }
 
   m_AddedDrawcall = false;