[PDB] Fix location retrieval for function local variables and arguments that are

stored relative to VFRAME

Summary:
This patch makes LLDB able to retrieve proper values for function arguments and
local variables stored in PDB relative to VFRAME register.

Patch contains retrieval of corresponding FPO table entries from PDB and a
generic translator from FPO programs to DWARF expressions to get correct VFRAME
value.

Patch also improves variables-locations.test and makes this test passable on
x86.

Patch By: leonid.mashinsky

Reviewers: zturner, asmith, stella.stamenova, aleksandr.urakov

Reviewed By: zturner

Subscribers: arphaman, labath, mgorny, aprantl, JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D55122

llvm-svn: 352845