move out TargetFileUtils

This is the only real thing in vts-core-tradefed-harness
that tests are using, so moving it to core tradefed.

Bug: 274790216
Test: atest FirmwareDtboVerification FirmwareBootHeaderVerification KernelSelinuxFileApiTest
Change-Id: I828ece56bcdd88e2e0f917e98917421474911c14
7 files changed