Add utf8_mode field to Settings and make Flags to reference it for init

I also changed the type from u8 to bool. No difference functionality-wise.

vm/src/stdlib/sys.rs

@@ -728,7 +728,7 @@ mod sys {
                 hash_randomization: settings.hash_seed.is_none() as u8,
                 isolated: settings.isolated as u8,
                 dev_mode: settings.dev_mode,
-                utf8_mode: 1,
+                utf8_mode: settings.utf8_mode,
                 int_max_str_digits: -1,
                 safe_path: false,
                 warn_default_encoding: settings.warn_default_encoding as u8,

vm/src/vm/setting.rs

@@ -74,6 +74,8 @@ pub struct Settings {
     /// false for wasm. Not a command-line option
     pub allow_external_library: bool,
 
+    pub utf8_mode: u8,
+
     #[cfg(feature = "flame-it")]
     pub profile_output: Option<OsString>,
     #[cfg(feature = "flame-it")]
@@ -107,6 +109,7 @@ impl Default for Settings {
             stdio_unbuffered: false,
             check_hash_based_pycs: "default".to_owned(),
             allow_external_library: cfg!(feature = "importlib"),
+            utf8_mode: 1,
             #[cfg(feature = "flame-it")]
             profile_output: None,
             #[cfg(feature = "flame-it")]