Mono/C#: Remove hard-coded debugger wait at initialization

Up until now debug builds would always wait up to 500 ms during initialization
to give time for debuggers to attach to the game.
We no longer want this as it increases startup time unnecesarily.
The way forward is to setup the debugger agent as client instead of server.
This way it's the game that connect to the debugger, not the other way around.
If server mode is still desired, suspend=y can be used to indefinitely wait
for the debugger to attach. This all can be specified with the environment
variable 'GODOT_MONO_DEBUGGER_AGENT' when launching the game.

modules/mono/mono_gd/gd_mono.cpp

@@ -119,28 +119,6 @@ void gd_mono_profiler_init() {
 
 #if defined(DEBUG_ENABLED)
 
-bool gd_mono_wait_for_debugger_msecs(uint32_t p_msecs) {
-
-	do {
-		if (mono_is_debugger_attached())
-			return true;
-
-		int last_tick = OS::get_singleton()->get_ticks_msec();
-
-		OS::get_singleton()->delay_usec((p_msecs < 25 ? p_msecs : 25) * 1000);
-
-		uint32_t tdiff = OS::get_singleton()->get_ticks_msec() - last_tick;
-
-		if (tdiff > p_msecs) {
-			p_msecs = 0;
-		} else {
-			p_msecs -= tdiff;
-		}
-	} while (p_msecs > 0);
-
-	return mono_is_debugger_attached();
-}
-
 void gd_mono_debug_init() {
 
 	mono_debug_init(MONO_DEBUG_FORMAT_MONO);
@@ -402,12 +380,6 @@ void GDMono::initialize() {
 	Error domain_load_err = _load_scripts_domain();
 	ERR_FAIL_COND_MSG(domain_load_err != OK, "Mono: Failed to load scripts domain.");
 
-#if defined(DEBUG_ENABLED) && !defined(JAVASCRIPT_ENABLED)
-	bool debugger_attached = gd_mono_wait_for_debugger_msecs(500);
-	if (!debugger_attached && OS::get_singleton()->is_stdout_verbose())
-		print_error("Mono: Debugger wait timeout");
-#endif
-
 	_register_internal_calls();
 
 	print_verbose("Mono: INITIALIZED");