avm2: Enable stack traces for Flash Player 11.5+

For Flash Player 11.5 and later, stack traces are always enabled.
Some content uses this behavior to verify whether the user is using
Flash Player 11.5 onwards.

See <https://docs.ruffle.rs/en_US/FlashPlatform/reference/actionscript/3/Error.html#getStackTrace()>

Author: kjarosh

core/src/avm2/object/error_object.rs

@@ -19,7 +19,16 @@ pub fn error_allocator<'gc>(
 ) -> Result<Object<'gc>, Error<'gc>> {
     let base = ScriptObjectData::new(class);
 
-    let call_stack = (enabled!(Level::INFO) || cfg!(feature = "avm_debug"))
+    // See <https://docs.ruffle.rs/en_US/FlashPlatform/reference/actionscript/3/Error.html#getStackTrace()>
+    let stack_trace_enabled =
+        // For Flash Player 11.5+, stack traces are always enabled.
+        activation.context.player_version >= 18
+        // For Flash Player 11.4 and earlier, stack traces are only enabled in debug builds.
+        || cfg!(feature = "avm_debug")
+        // But also allow enabling them with log level >= INFO.
+        || enabled!(Level::INFO);
+
+    let call_stack = stack_trace_enabled
         .then(|| activation.avm2().call_stack().borrow().clone())
         .unwrap_or_default();