gh-102856: Python tokenizer implementation for PEP 701 (#104323)

This commit replaces the Python implementation of the tokenize module with an implementation
that reuses the real C tokenizer via a private extension module. The tokenize module now implements
a compatibility layer that transforms tokens from the C tokenizer into Python tokenize tokens for backward
compatibility.

As the C tokenizer does not emit some tokens that the Python tokenizer provides (such as comments and non-semantic newlines), a new special mode has been added to the C tokenizer mode that currently is only used via
the extension module that exposes it to the Python layer. This new mode forces the C tokenizer to emit these new extra tokens and add the appropriate metadata that is needed to match the old Python implementation.

Co-authored-by: Pablo Galindo <pablogsal@gmail.com>

Parser/token.c

@@ -70,9 +70,9 @@ const char * const _PyParser_TokenNames[] = {
     "FSTRING_START",
     "FSTRING_MIDDLE",
     "FSTRING_END",
+    "COMMENT",
+    "NL",
     "<ERRORTOKEN>",
-    "<COMMENT>",
-    "<NL>",
     "<ENCODING>",
     "<N_TOKENS>",
 };