Add missing locale requirement to test.

Linux is failing even though the test runner does report this locale
is available, but the test still isn't expected to work on platforms
without the locale (like Android).

llvm-svn: 359726

libcxx/test/std/re/re.alg/re.alg.match/awk.pass.cpp

@@ -19,6 +19,7 @@
 // TODO: investigation needed
 // TODO(netbsd): incomplete support for locales
 // XFAIL: linux-gnu, netbsd
+// REQUIRES: locale.cs_CZ.ISO8859-2
 
 #include <regex>
 #include <cassert>