Replace old implementations with new ones

Author: rtfeldman

src/base/Region.zig

@@ -26,6 +26,10 @@ pub fn zero() Self {
     };
 }
 
+pub fn empty() Self {
+    return zero();
+}
+
 /// Create a `Region` from raw offsets.
 pub fn from_raw_offsets(start: u32, end: u32) Self {
     std.debug.assert(start <= end);