This enables us to handle different ASan versions with the same runtime.
Previous version bumps were due to the following reasons (check
Struct layout changes: v2, v4, v7
Function existence/arguments changes: v5, v6, v8
Miscellaneous additional data structures changes: v3
It is possible to support these kinds of changes *if* we know which
version we're dealing with.
Our plan is to internally ship a library with more than one
__asan_version_mismatch_check_v*, and have those functions setup
function pointers to deal appropriately with the structures added by the
compiler. We will not allow more than one version per executable run
(all modules), though, as that would add too much complexity for little