Remove xfail tag for darwin from quick_exit test

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@222406 91177308-0d34-0410-b5e6-96231b3b80d8

test/language.support/support.start.term/quick_exit.pass.cpp

diff --git a/test/language.support/support.start.term/quick_exit.pass.cpp b/test/language.support/support.start.term/quick_exit.pass.cpp
index 3d95039..bcfdbb7 100644
--- a/test/language.support/support.start.term/quick_exit.pass.cpp
+++ b/test/language.support/support.start.term/quick_exit.pass.cpp
@@ -7,7 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// XFAIL: apple-darwin
 
 // test quick_exit and at_quick_exit