[libcxxabi] Use 'target=' consistently

Author: pogo59

libcxxabi/test/catch_function_03.pass.cpp

@@ -11,7 +11,7 @@
 // UNSUPPORTED: no-exceptions
 
 // Support for catching a function pointer including noexcept was shipped in macOS 10.13
-// XFAIL: use_system_cxx_lib && {{.+}}-apple-macosx10.{{9|10|11|12}}
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}}
 
 #include <cassert>
 

libcxxabi/test/catch_member_function_pointer_02.pass.cpp

@@ -11,7 +11,7 @@
 // UNSUPPORTED: no-exceptions
 
 // Support for catching a function pointer including noexcept was shipped in macOS 10.13
-// XFAIL: use_system_cxx_lib && {{.+}}-apple-macosx10.{{9|10|11|12}}
+// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}}
 
 // GCC supports noexcept function types but this test still fails.
 // This is likely a bug in their implementation. Investigation needed.