Use getattr instead

Created using spr 1.3.6-beta.1

Author: pcc

libcxx/test/libcxx/gdb/gdb_pretty_printer_test.py

@@ -30,7 +30,7 @@
 # we exit.
 has_run_tests = False
 
-has_execute_mi = "execute_mi" in gdb.__dict__
+has_execute_mi = getattr(gdb, "execute_mi", None) is not None
 
 
 class CheckResult(gdb.Command):