[libcxx] updates the feature-test macro generator

D97015 didn't correctly update `generate_feature_test_macro_components.py`.

Reviewed By: ldionne, Quuxplusone, #libc, Mordante

Differential Revision: https://reviews.llvm.org/D97904

GitOrigin-RevId: 580416d573b6e5d33c09467084e382ac78f2a199
4 files changed