[lldb] Consider binary as module of last resort

When setting an address breakpoint using a non-section address in lldb
before having ever run the program, the binary itself is not considered
a module. As a result, the breakpoint is unresolved (and never gets
resolved subsequently).

This patch changes that behavior: as a last resort, the binary is
considered as a module when resolving a non-section address breakpoint.

Differential revision: https://reviews.llvm.org/D124731