Recently problems have been discovered in the way we write the FPM
(free page map). In order to fix this, we first need to establish
a baseline about what a correct FPM looks like using an MSVC
generated PDB, so that we can then make our own generated PDBs
match. And in order to do this, the dumper needs a mode where it
can dump an FPM so that we can write tests for it.
This patch adds a command to dump the FPM, as well as a test against
a known-good PDB.
llvm-svn: 309894
