[lldb] Use current breakpoint location in TestBreakpointLocationDot.py (NFC) (#197472)
Replaces `FindLocationByID(1)` with `FindLocationByID(loc_id)`. Instead
of hard-coding an ID of 1, the location ID is determined from
`GetStopReasonDataAtIndex`.
Some of these asserts were failing on a windows CI, because the
breakpoint was resolved to **two** locations.