[libc] Add C23 binary prefix support to strtointeger (#202243)

The C23 standard (N3220 §7.24.1.7) requires strtol and related functions
to recognize the 0b/0B prefix when base is 2 or 0. This change
implements that support and adds relevant tests.

Assisted by: Claude Sonnet 4.6 for generating and understanding Tests.

Co-authored-by: shubhe25p <shubhp@Mac.lan>
GitOrigin-RevId: 27dc2ec9b323edbb76e56388dbc8064a5109f430