[lldb/ObjectFileMachO] Correctly account for resolver symbols

Summary:
The resolver addresses stored in the dyld trie are relative to the base
of the __TEXT segment. This is usually 0 in a dylib, so this was never
noticed, but it is not 0 for most dylibs integrated in the shared cache.
As we started using the shared cache images recently as symbol source,
this causes LLDB to fail to resolve symbols which go through a runtime
resolver.

Reviewers: jasonmolenda, jingham

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D84083