[libcxx] Fix incorrect XFAILs for chrono tests on old macos deployment targets

The tests were marked to fail based on the 'availability' LIT feature.
However, those tests should really only be failing when we run them
against the dylibs that were deployed on macosx10.7 and macosx10.8,
which the deployment target has nothing to do with.

This caused the tests to unexpectedly pass when running the tests
with deployment target macosx10.{7,8} but running with a recent dylib.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@348520 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp b/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
index 2f8a707..47a610f 100644
--- a/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
+++ b/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
@@ -12,9 +12,10 @@
 // UNSUPPORTED: asan
 
 // Starting with C++17, Clock::is_steady is inlined (but not before LLVM-3.9!),
-// but before C++17 it requires the symbol to be present in the dylib.
-// XFAIL: availability=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
-// XFAIL: availability=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// but before C++17 it requires the symbol to be present in the dylib, which
+// is only shipped starting with macosx10.9.
+// XFAIL: with_system_cxx_lib=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// XFAIL: with_system_cxx_lib=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
 
 // <chrono>
 
diff --git a/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp b/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
index 4458d6f..e5e6de2 100644
--- a/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
+++ b/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
@@ -14,9 +14,10 @@
 // UNSUPPORTED: asan
 
 // Starting with C++17, Clock::is_steady is inlined (but not before LLVM-3.9!),
-// but before C++17 it requires the symbol to be present in the dylib.
-// XFAIL: availability=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
-// XFAIL: availability=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// but before C++17 it requires the symbol to be present in the dylib, which
+// is only shipped starting with macosx10.9.
+// XFAIL: with_system_cxx_lib=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// XFAIL: with_system_cxx_lib=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
 
 // <chrono>
 
diff --git a/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp b/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
index deb4615..c5ecb32 100644
--- a/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
+++ b/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
@@ -12,9 +12,10 @@
 // UNSUPPORTED: asan
 
 // Starting with C++17, Clock::is_steady is inlined (but not before LLVM-3.9!),
-// but before C++17 it requires the symbol to be present in the dylib.
-// XFAIL: availability=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
-// XFAIL: availability=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// but before C++17 it requires the symbol to be present in the dylib, which
+// is only shipped starting with macosx10.9.
+// XFAIL: with_system_cxx_lib=macosx10.7 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
+// XFAIL: with_system_cxx_lib=macosx10.8 && (c++98 || c++03 || c++11 || c++14 || apple-clang-7 || apple-clang-8.0)
 
 // <chrono>