[llvm-pdbutil] Fix some dumping issues.

When dumping, we were treating the S_INLINESITESYM as referring
to a type record, when it actually refers to an id record.  We
had this correct in TypeIndexDiscovery, so our merging algorithm
should be fine, but we had it wrong in the dumper, which means it
would appear to work most of the time, unless the index was out
of bounds in the type stream, when it would fail.  Fixed this, and
audited a few other cases to make them match the behavior in
TypeIndexDiscovery.

Also, I've now observed a new symbol record with kind 0x1168 which
I have no clue what it is, so to avoid crashing we have to just
print "Unknown Symbol Kind".

llvm-svn: 311117