The `if not probe_proc_self_mem` check never passes, because
probe_proc_self_mem is a function object, which is a truthy value.
Add parentheses in order to perform a function call.
Fixes: dc84d50a7f9b ("tests/tcg: Add the PROT_NONE gdbstub test")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240131220245.235993-1-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>