gst-validate-launcher: disable timeouts when debugging in gdb interactively

An interactive debugging session can be going for a long time, we don't
want any timeouts in that case.

https://bugzilla.gnome.org/show_bug.cgi?id=796397

validate/launcher/baseclasses.py

@@ -385,6 +385,11 @@ class Test(Loggable):
         if self.hard_timeout is not None:
             self.hard_timeout *= GDB_TIMEOUT_FACTOR
         self.timeout *= GDB_TIMEOUT_FACTOR
+
+        if not self.options.gdb_non_stop:
+            self.timeout = sys.maxsize
+            self.hard_timeout = sys.maxsize
+
         args = ["gdb"]
         if self.options.gdb_non_stop:
             args += ["-ex", "run", "-ex", "backtrace", "-ex", "quit"]