Support turning installed wheel chroots into `.whl` files with full fidelity.

[jsirois]

If we can round trip from a downloaded .whl to an installed wheel chroot and back with full fidelity, then we can fix a long existing latent bug and improve composability of Pex options:

• Unreported bug: PEX_TOOLS=1 ./a.pex repository extract ... does not produce correct wheels when the original wheel contains any data dirs (<project>-<version>.data/* .whl zip file entries).
• --pex-repository: via #2298 a PEX repository with dependency .whl files can satisfy .whl file resolves and installed wheel chroot resolves but a PEX repository with installed wheel chroot dependencies can only satisfy resolves for installed wheel chroot dependencies and not for .whl files.