Install more debug symbols for ASAN builds

Install glib and gtk symbols which are required to get full information
from the LeakSanitizer stack traces.

build/tools/before_install.sh

@@ -61,7 +61,7 @@ case $(uname -s) in
                 $SUDO apt-get update
 
                 # Install the symbols to allow LSAN suppression list to work.
-                $SUDO apt-get install -y libfontconfig1-dbgsym
+                $SUDO apt-get install -y libfontconfig1-dbgsym libglib2.0-0-dbgsym libgtk-3-0-dbgsym
             fi
         fi
         ;;