[lldb] Access the ModuleList through iterators where possible (NFC)

Replace uses of GetModuleAtIndexUnlocked and
GetModulePointerAtIndexUnlocked with the ModuleIterable and
ModuleIterableNoLocking where applicable.

Differential revision: https://reviews.llvm.org/D94271

GitOrigin-RevId: f2e05855deb39125a30a67b63a5e524792805768
16 files changed