header-checker: Reorder command line option checks

This commit reorders the command line option checks for
`header-abi-dumper` so that `header-abi-dumper -help` can print help
messages without problems.

Test: header-abi-dumper -help
Change-Id: I391f1e697cde44f4edce9f0008c5f39f938dc967
1 file changed