Development/scripts: Update stack tool

The tool was broken for ASAN traces. Add a missing key to the
dictionary.

Bug: 24133462
Change-Id: I6e5b60441c9c602cd1381c1cb32947a1425c7069

scripts/stack_core.py

@@ -195,6 +195,7 @@ class TraceConverter:
       match = self.sanitizer_trace_line.match(line)
       return {"frame": match.group("frame"),
               "offset": match.group("offset"),
+              "so_offset": None,
               "dso": match.group("dso"),
               "symbol_present": False,
               "symbol_name": None}