Run layout-transitivity test only when debugging is enabled.

Because it depends on "-mllvm -debug" flag, the test fails in Release build.

llvm-svn: 193271

lld/test/core/layout-transitivity.objtxt

@@ -1,10 +1,6 @@
+# REQUIRES: debug
 # RUN: lld -core --add-pass layout -mllvm -debug %s 2> /dev/null | FileCheck %s
 
-# For some reason this test is failing on Darwin and FreeBSD probably because
-# of assertion error, while this test seems to be platform-neutral. Disable
-# for now.
-# XFAIL: darwin, freebsd
-
 ---
 defined-atoms:
   - name:            fn3