The pre-loaded GTK library version cannot be detected by AWT Toolkit when being embedded in SWT

If GTK libraries have different versions an attempt to load them in the same process will cause fatal error.

After the JDK-8145547 JDK may work with 2 versions of GTK: 2 and 3 and has a built-in mechanism to detect the library version it should use to avoid loading of incompatible library version. This mechanism tries to detect if the certain version of GTK is pre-loaded in the process. But it fails to detect this in case of SWT embedding.

Test AWT_SWT/Manual/SwingComp/SwingAppTest.java crashes with GTK LnF, unless the GTK version is set manually to 3: -Djdk.gtk.version=3.