gitignore: Update

* Ignore .qmake files
* Ignore test binaries

Change-Id: I6571cfc219641c36c558d7de127c7198c98c1476
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

.gitignore

@@ -30,4 +30,8 @@ qrc_*.cpp
 Makefile*
 *.html
 *~
-.qmake.cache
+.qmake.*
+
+tst_*
+!tst_*.*
+tst_*.exe