package/uclibc-ng-test: disable tst-cond22 with glibc based toolchain

uclibc-ng-test is broken with glibc 2.25 due to pthread_cond_t changes
introduced by [1].
Waldemar has disabled this test (tst-cond22) with glibc based toolchain
[2] but the current uclibc-ng-test package doesn't contain this patch.

So here it is.

Fixes:
[nios2] http://autobuild.buildroot.net/results/d61c8d169fc070271114a515159650f7a0f333c0
[arm] http://autobuild.buildroot.net/results/22295711046c519df44d5d976e0bfcae1f006e5a

[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=ed19993b5b0d05d62cc883571519a67dae481a14
[2] https://gogs.waldemar-brodkorb.de/linux/uclibc-ng-test/commit/787e584f18afc967d91cfe1a8443df2657579ecb



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>