When attempting to find the callsite for a DwarfDie to see if it was
valid or not, there was a while loop that incorrectly attempted to walk
up the Die parent hierarch. It set `curr` to parent, but then `curr` was
set to same original parent instead of curr.getParent(). This caused
infinite recursion on validation of some kernel binaries by
llvm-dwarfdump where DW_TAG_call_site was nested inside a
DW_TAG_lexical_block (or any non-subprogram, non-inlined_subroutine
tag).
Fix by changing Die.getParent() to Curr.getParent() so the loop
correctly walks up the DIE tree.
Add a new test that validates this scenario. Without this change, that
test hangs rather than succeeding.
3088f1fffa