Support loading files even when incorrect file name specified by the linker

Support loading files even when incorrect file name specified by the linker

"Incorrect" file name seen on Android whene the main executable is
called "app_process32" (or 64) but the linker specifies the package
name (e.g. com.android.calculator2). Additionally it can be present
in case of some linker bugs.

This CL adds logic to try to fetch the correct file name from the proc
file system based on the base address sepcified by the linker in case
we are failed to load the module by name.

Differential revision: http://reviews.llvm.org/D22219

llvm-svn: 276411