Run layout-transitivity test only when debugging is enabled.
Run layout-transitivity test only when debugging is enabled.

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

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@193271 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld