[Sanitizer] Extend a symbolizer code. Implemented for Linux only. Use...

[Sanitizer] Extend a symbolizer code. Implemented for Linux only. Use dl_iterate_phdr to get virtual addresses of mapped module sections. To symbolize an address from a module, map this module to memory and obtain pointers to debug info sections. Later these pointers can be passed to constructor of DWARF context-in-memory from LLVM DebugInfo lib.

llvm-svn: 159652