Do not check if known locations exist on host for hidden API

Hidden API access checks compare the domains of the caller and the
callee which are set based on the locations of their respective dex
files. When preopting on host, these are the expected paths on target
but helper functions in file_utils.h used to check whether they exist
on the local filesystem. This resulted in not always assigning the
same domains as when running on target.

With this CL, the functions ignore the DirectoryExists check on host.

Test: art/test/testrunner/run_build_test_target.py art-test
Bug: 129063331
Merged-In: I1143e94a31e3ee8303db07469cc03959ab5732b7
Change-Id: I1143e94a31e3ee8303db07469cc03959ab5732b7
(cherry picked from commit 2df4bfb2abf922a3c7972333f2bcc9655b122080)