ci: runs SWT on real UI thread

Author: AndriiFilippov

tests/pom.xml

@@ -27,7 +27,7 @@
 				<version>${tycho-version}</version>
 				<configuration>
 					<useUIHarness>true</useUIHarness>
-					<useUIThread>false</useUIThread>
+					<useUIThread>true</useUIThread>
 					<application>org.eclipse.ui.ide.workbench</application>
 					<!-- Debugging helper arguments   -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=0.0.0.0:8989 -->
 					<argLine>-Xms4096m -Xmx8192m -DtestRun=true</argLine>