dwarfdump: Avoid parsing units unnecessarily

NFC-ish (the parsing of the units is not a functional change - no
errors/warnings are emitted during the shallow parsing - though without
parsing them here, the "max version" would be wrong (still zero) later
on, so in those cases the units do need to be parsed)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343884 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed