Minidump plugin: functions parsing memory structures and filtering module list

Summary:
Now the Minidump parser can parse the:
1) MemoryInfoList - containing region info about memory ranges (readable,
writable, executable)
2) Memory64List - this is the stuct used when the Minidump is a
full-memory one.
3) Adding filtering of the module list (shared libraries list) - there
can be mutliple records in the module list under the same name but with
different load address (e.g. when the binary has non contigious
sections). FilterModuleList eliminates the duplicated modules, leaving
the one with the lowest load addr.

Added unit tests for everything.

Reviewers: labath, zturner

Subscribers: beanz, mgorny, modocache, lldb-commits, amccarth

Differential Revision: https://reviews.llvm.org/D25569

llvm-svn: 284593