[lldb] Upstream and adopt ReadUnsignedIntegersFromMemory in AppleObjCRuntimeV2 (#190564)
This PR upstreams ReadUnsignedIntegersFromMemory, which uses the
MultiMemRead packet to speed up reading unsigned numbers from memory.
Felipe landed this on Github because we didn't have a use-case for it
upstream, until now, which uses it to batch up reading ObjC runtime
symbols.