Add linux/userfaultfd.h header file to host glibc

Userfaultfd-based GC in ART needs the header file for host builds.
The file is copied from bionic(4e5f0944619792aef63ebc3afc0df78205c89954).

Test: art/test/testrunner/testrunner.py --host
Bug: 73747445
Change-Id: Id7a93060201ba3f2b2611d5aa324793256173a71
2 files changed