Skip three test cases that are asserting on macosx as of r299199. A quick

look showed that the target's arch has no core / byte order and so when
AuxVector::AuxVector calls into a dataextractor and sets the byte size to 0,
it asserts.  e.g.

  m_arch = {
    m_triple = (Data = "x86_64--linux", Arch = x86_64, SubArch = NoSubArch, Vendor = UnknownVendor, OS = Linux, Environment = UnknownEnvironment, ObjectFormat = ELF)
    m_core = kCore_invalid
    m_byte_order = eByteOrderInvalid
    m_flags = 0x00000000
    m_distribution_id = <no value available>
  }

<rdar://problem/31380097> 

llvm-svn: 299408