Fix looping test regression due to a.out

mjtest/test/exec_tests.py

@@ -209,7 +209,7 @@ class JavaInfiniteLoopTest(BasicSyntaxTest):
                 return test_result
         except SigKill as sig:
             if sig.retcode == signal.SIGXCPU:
-                out, _, _, _ = self.env.run_command_till_timeout("./" + base_filename, timeout=1)
+                out, _, _, _ = self.env.run_command_till_timeout("./a.out", timeout=1)
                 test_result.add_long_text("Output", out.decode())
                 if self._has_output_file:
                     out = out.decode().strip()