core_timing: Allow configuring a fixed or random initial system tick value. (#7309)

* core_timing: Apply random base ticks value on startup.

* core: Maintain consistent base system ticks in TAS movies.

* frontend: Add setting to configure a fixed base system ticks value.

src/citra/config.cpp

@@ -225,6 +225,8 @@ void Config::ReadValues() {
                 std::chrono::system_clock::from_time_t(std::mktime(&t)).time_since_epoch())
                 .count();
     }
+    ReadSetting("System", Settings::values.init_ticks_type);
+    ReadSetting("System", Settings::values.init_ticks_override);
     ReadSetting("System", Settings::values.plugin_loader_enabled);
     ReadSetting("System", Settings::values.allow_plugin_loader);
 

src/citra/default_ini.h

@@ -307,6 +307,14 @@ init_clock =
 # Note: 3DS can only handle times later then Jan 1 2000
 init_time =
 
+# The system ticks count to use when citra starts
+# 0: Random (default), 1: Fixed
+init_ticks_type =
+
+# Tick count to use when init_ticks_type is set to Fixed.
+# Defaults to 0.
+init_ticks_override =
+
 [Camera]
 # Which camera engine to use for the right outer camera
 # blank (default): a dummy camera that always returns black image