Add decorator for intermittently failing test on FreeBSD

This test has intermittently failed on FreeBSD for quite some time when
run as part of the full test suite.  It generally passes when run by
itself.  Mark as expected failure for now to reduce buildbot noise.

llvm.org/pr15039 test fails intermittently on FreeBSD


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222134 91177308-0d34-0410-b5e6-96231b3b80d8
Whitespace cleanup and remove non-canonical headers



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222135 91177308-0d34-0410-b5e6-96231b3b80d8
Fix Darwin and FreeBSD OS type detection

Obtained in part from http://reviews.llvm.org/D6290


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222136 91177308-0d34-0410-b5e6-96231b3b80d8