coroutines, testsuite: Renumber two tests (NFC).

Try to keep tests order by distinct number (and with a short
descriptive name appended).

2020-04-05  Iain Sandoe  <iain@sandoe.co.uk>

	* g++.dg/coroutines/torture/co-await-14-template-traits.C: Rename...
	* g++.dg/coroutines/torture/co-await-16-template-traits.C: to this.
	* g++.dg/coroutines/torture/co-await-15-capture-comp-ref.C: Rename..
	* g++.dg/coroutines/torture/co-await-17-capture-comp-ref.C: to this.

gcc/testsuite/ChangeLog

+2020-04-05  Iain Sandoe  <iain@sandoe.co.uk>
+
+	* g++.dg/coroutines/torture/co-await-14-template-traits.C: Rename...
+	* g++.dg/coroutines/torture/co-await-16-template-traits.C: to this.
+	* g++.dg/coroutines/torture/co-await-15-capture-comp-ref.C: Rename..
+	* g++.dg/coroutines/torture/co-await-17-capture-comp-ref.C: to this.
+
 2020-04-05  Nagaraju Mekala  <nmekala@xilix.com>
 
 	* gcc.target/microblaze/others/builtin-trap.c: Update expected output.