[asan] Add a new AddressDescription structure, which can describe any type of address.

[asan] Add a new AddressDescription structure, which can describe any type of address.

Summary:
This is useful for inclusion in the Error* structures, to describe an
arbitrary address.

Remove the old struct since it's used only once. This removes one level of
indirection, and moves all *AddressDescription to be one of the recently
introduced structures.

This merges differential revisions: D24131 and D24132

Reviewers: kcc, eugenis, vitalybuka

Subscribers: kubabrecka, llvm-commits

Differential Revision: https://reviews.llvm.org/D24131

llvm-svn: 281090