FindHDF5: Fix command-line parsing argument extraction order

Re-implement our internal `_HDF5_parse_compile_line` helper to process
command line arguments all at once and in order.  Otherwise the
libraries named by absolute path and those named by `-l` arguments are
not kept in order.

The new implementation will not handle separate arguments like
`-I /path/to/include/dir` but I have not seen the HDF5 compiler
wrappers produce this form.  If necessary the parsing loop can
be extended with a state variable to keep track of such pairs.