/DISCARD/ in ld testsuite

The canonical form to discard all sections not mentioned earlier in
the script is
  /DISCARD/ : { *(*) }
not
  /DISCARD/ : { *(.*) }
".*" happens to work with the usual section names starting with a dot,
but let's not promote something not quite right.

ld/testsuite/ld-scripts/empty-address-3a.t

@@ -7,5 +7,5 @@ SECTIONS
   }
   __data_end = .;
   .bss : { *(.bss) }
-  /DISCARD/ : { *(.*) }
+  /DISCARD/ : { *(*) }
 }