[libcxx][test] Correct syntax of lit directives in some tests (#146886)

"XFAIL " does not do anything, you need to have the colon afterwards.
"XFAIL: ".

Found by searching for: (XFAIL|REQUIRES|UNSUPPORTED)[^:]

Author: DavidSpickett

libcxx/test/libcxx/input.output/iostreams.base/ios.base/ios.base.cons/dtor.uninitialized.pass.cpp

@@ -13,7 +13,7 @@
 
 // The fix for issue 57964 requires an updated dylib due to explicit
 // instantiations. That means Apple backdeployment targets remain broken.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 // <ios>
 

libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/setbuf.pass.cpp

@@ -15,7 +15,7 @@
 
 // This test requires the fix to https://github.com/llvm/llvm-project/issues/60509 in the dylib,
 // which landed in 5afb937d8a30445642ccaf33866ee4cdd0713222.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 #include <fstream>
 #include <cstddef>

libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/sync.pass.cpp

@@ -16,7 +16,7 @@
 // The fix for bug 51497 and bug 51499 require and updated dylib due to
 // explicit instantiations. That means Apple backdeployment targets remain
 // broken.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 #include <istream>
 #include <cassert>

libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp

@@ -9,7 +9,7 @@
 // TODO(mordante) Investigate
 // UNSUPPORTED: apple-clang
 
-// XFAIL darwin
+// XFAIL: darwin
 
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd

libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp

@@ -9,7 +9,7 @@
 // TODO(mordante) Investigate
 // UNSUPPORTED: apple-clang
 
-// XFAIL darwin
+// XFAIL: darwin
 
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd

libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/grouping.pass.cpp

@@ -9,7 +9,7 @@
 // TODO(mordante) Investigate
 // UNSUPPORTED: apple-clang
 
-// XFAIL darwin
+// XFAIL: darwin
 //
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd

libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp

@@ -11,7 +11,7 @@
 
 // The fix for LWG2381 (https://github.com/llvm/llvm-project/pull/77948) changed behavior of
 // FP parsing. This requires 3e15c97fa3812993bdc319827a5c6d867b765ae8 in the dylib.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 // <locale>
 

libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp

@@ -11,7 +11,7 @@
 
 // The fix for LWG2381 (https://github.com/llvm/llvm-project/pull/77948) changed behavior of
 // FP parsing. This requires 3e15c97fa3812993bdc319827a5c6d867b765ae8 in the dylib.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 // <locale>
 

libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp

@@ -11,7 +11,7 @@
 
 // The fix for LWG2381 (https://github.com/llvm/llvm-project/pull/77948) changed behavior of
 // FP parsing. This requires 3e15c97fa3812993bdc319827a5c6d867b765ae8 in the dylib.
-// XFAIL using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 // <locale>