[asan] Fix nonsensical reports of partial right OOB.

In case of partial right OOB, ASan was reporting
  X is located 0 bytes to the right of [A, B)
where X was actually inside [A, B).

With this change, ASan will report B as the error address in such case.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@174373 91177308-0d34-0410-b5e6-96231b3b80d8