Fix smelly tests

Author: pablogsal

Parser/action_helpers.c

@@ -1197,7 +1197,7 @@ _PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args, asdl_comprehension_seq
 
 // Fstring stuff
 
-expr_ty
+static expr_ty
 decode_fstring_buffer(Parser *p, int lineno, int col_offset, int end_lineno,
                       int end_col_offset)
 {

Parser/tokenizer.c

@@ -44,7 +44,7 @@
             tok->col_offset = 0;
 
 /* Forward */
-struct tok_state *tok_new(void);
+static struct tok_state *tok_new(void);
 static int tok_nextc(struct tok_state *tok);
 static void tok_backup(struct tok_state *tok, int c);
 static int syntaxerror(struct tok_state *tok, const char *format, ...);
@@ -55,7 +55,7 @@ static const char* type_comment_prefix = "# type: ";
 
 /* Create and initialize a new tok_state structure */
 
-struct tok_state *
+static struct tok_state *
 tok_new(void)
 {
     struct tok_state *tok = (struct tok_state *)PyMem_Malloc(