[dfsan] Wrap glibc 2.38 __isoc23_* functions (#79958)

Fix #79283: `test/dfsan/custom.cpp` has undefined symbol linker errors
on glibc 2.38 due to lack of wrappers for `__isoc23_strtol` and
`__isoc23_scanf` family functions.

Implement these wrappers as aliases to existing wrappers, similar to
https://reviews.llvm.org/D158943 for other sanitizers.

`strtol` in a user program, whether or not `_ISOC2X_SOURCE` is defined,
uses the C23 semantics (`strtol("0b1", 0, 0)` => 1), when
`libclang_rt.dfsan.a` is built on glibc 2.38+.