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).

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@359726 91177308-0d34-0410-b5e6-96231b3b80d8

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>