[lldb][testing] Check all stop reasons in get_threads_stopped_at_breakpoint_id (llvm#108281)

If multiple breakpoints are hit at the same time, multiple stop reasons
are reported, one per breakpoint.

Currently, `get_threads_stopped_at_breakpoint_id` only checks the first
such reason.

(cherry picked from commit 7e74472)

Author: felipepiovezan

lldb/packages/Python/lldbsuite/test/lldbutil.py

@@ -784,9 +784,16 @@ def get_threads_stopped_at_breakpoint_id(process, bpid):
         return threads
 
     for thread in stopped_threads:
-        # Make sure we've hit our breakpoint...
-        break_id = thread.GetStopReasonDataAtIndex(0)
-        if break_id == bpid:
+        # Make sure we've hit our breakpoint.
+        # From the docs of GetStopReasonDataAtIndex: "Breakpoint stop reasons
+        # will have data that consists of pairs of breakpoint IDs followed by
+        # the breakpoint location IDs".
+        # Iterate over all such pairs looking for `bpid`.
+        break_ids = [
+            thread.GetStopReasonDataAtIndex(idx)
+            for idx in range(0, thread.GetStopReasonDataCount(), 2)
+        ]
+        if bpid in break_ids:
             threads.append(thread)
 
     return threads