Ignore the str field of ast.Interpolation

This seems like a mis-feature - we can already get the source text if we want it. It shouldn't be part of the AST node.

Author: dflook

src/python_minifier/ast_compare.py

@@ -63,6 +63,9 @@ def counter():
 
         if field == 'kind' and isinstance(l_ast, ast.Constant):
             continue
+        
+        if field == 'str' and hasattr(ast, 'Interpolation') and isinstance(l_ast, ast.Interpolation):
+            continue
 
         if isinstance(getattr(l_ast, field, None), list):