bpo-42519: Replace PyMem_MALLOC() with PyMem_Malloc() (GH-23586)

No longer use deprecated aliases to functions:

* Replace PyMem_MALLOC() with PyMem_Malloc()
* Replace PyMem_REALLOC() with PyMem_Realloc()
* Replace PyMem_FREE() with PyMem_Free()
* Replace PyMem_Del() with PyMem_Free()
* Replace PyMem_DEL() with PyMem_Free()

Modify also the PyMem_DEL() macro to use directly PyMem_Free().
diff --git a/Parser/string_parser.c b/Parser/string_parser.c
index 8f6433d..09b8c35 100644
--- a/Parser/string_parser.c
+++ b/Parser/string_parser.c
@@ -384,7 +384,7 @@ fstring_compile_expr(Parser *p, const char *expr_start, const char *expr_end,
 
     int lines, cols;
     if (!fstring_find_expr_location(t, str, &lines, &cols)) {
-        PyMem_FREE(str);
+        PyMem_Free(str);
         return NULL;
     }