[llvm-pdbutil] Dump more info about globals.

We add an option to dump the entire global / public symbol record
stream.  Previously we would dump globals or publics, but not both.
And when we did dump them, we would always dump them in the order
they were referenced by the corresponding hash streams, not in
the order they were serialized in.  This patch adds a lower level
mode that just dumps the whole stream in serialization order.

Additionally, when dumping global-extras, we now dump the hash
bitmap as well as the record offset instead of dumping all zeros
for the offsets.

llvm-svn: 336407