7124551: [macosx] Once added, Menu shortcut cannot be removed

Reviewed-by: art, anthony

src/macosx/native/sun/awt/CMenuItem.m

@@ -125,11 +125,8 @@ AWT_ASSERT_NOT_APPKIT_THREAD;
 
     [JNFRunLoop performOnMainThreadWaiting:YES withBlock:^(){
         AWT_ASSERT_APPKIT_THREAD;
-
-        if (![theKeyEquivalent isEqualToString:@""]) {
         [fMenuItem setKeyEquivalent:theKeyEquivalent];
         [fMenuItem setKeyEquivalentModifierMask:modifierMask];
-        }
         [fMenuItem setTitle:theLabel];
     }];
 }