core: Empty text lines should still have a height.

core/src/font.rs

@@ -5,6 +5,7 @@ use gc_arena::{Collect, Gc, MutationContext};
 use ruffle_render::backend::{RenderBackend, ShapeHandle};
 use ruffle_render::transform::Transform;
 use std::cell::{Cell, Ref, RefCell};
+use std::cmp::max;
 
 pub use swf::TextGridFit;
 
@@ -314,6 +315,10 @@ impl<'gc> Font<'gc> {
             },
         );
 
+        if text.is_empty() {
+            height = max(height, params.height);
+        }
+
         (width, height)
     }