Increase some test timeouts.

Increase some test timeouts.

This patch increases the timeouts for some tests that I've seen timing
out on slow systems in my 2.26 release testing.  (In the case of
tst-tsearch.c, increasing the timeout means removing a setting of 10
that was put there before the default timeout was increased to 20
seconds, so putting the default into effect.)

	* iconvdata/tst-loading.c (TIMEOUT): Define to 30.
	* misc/tst-tsearch.c (TIMEOUT): Remove.
	* nptl/tst-create-detached.c (TIMEOUT): Define to 100.
	* nptl/tst-robust-fork.c (TIMEOUT): Likewise.
	* nptl/tst-rwlock19.c (TIMEOUT): Likewise.
	* string/tst-cmp.c (TIMEOUT): Define to 600.