When building with a Default Target set we can experience issues in the DWARF DebugInfo unit tests because:
- They assume we can generate object files for the host platform
- Some tests assume the endianess of the target we are generating DWARF for and the host match
This patch correct these issues by ensuring the tests which generate objects in memory are run with respect to LVM_DEFAULT_TARGET_TRIPLE and it's
endianess. We also make sure we don't use the hosts address size for line test and split the triple util function in DwarfUtils into a version that takes an address size and one that doesn't.
See also for discussion: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131212.html