[ASan] Introduce the dump_instruction_bytes flag to print the faulting instruction upon SIGSEGV

When dump_instruction_bytes=1 and the instruction pointer doesn't point to the zero page, ASan prints 16 bytes starting at the instruction point.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@218243 91177308-0d34-0410-b5e6-96231b3b80d8