Fix a typo made in Programmer's Manual made in r210354. Spotted
by Paul Robinson.
Match the full hex offsets in test/DebugInfo/X86/gnu-public-names.ll

These checks were accidentally skipping the 0x prefix in the hex
offsets, then cunningly ignoring the prefix in the use of those captured
values.

Except in the case of the unit length, where the match was only matching
the leading '0' before the x in the 0x prefix, then matching that
against the length. We can't actually express the length association
here, as the length field in the Compile Unit header does not include
the length field itself, but the length field in the pubnames section
/does/ include the size of the length field in the Compile Unit header -
so the two numbers are actually 4 bytes different. Just skip matching
that.