MCJIT emits zero-length CIE at the end of the _eh_frame section. This change
ensures that parser inside DebugInfo will not crash and correctly record such cases.
We are now recording DW_EH_PE_omit as a default value for FDE and LSDA encodings.
This seems to be in sync with MCDwarf.cpp _eh_frame emitter. Also Offset != EndAugmentationOffset
assertion check will only happen if augmentation string had 'z' letter in it.
Unfortunately I couldn't think of an easy way to write llvm-lit tests for this.
However feature seems simple enough to survive using existing tests.