Revert "Generate the ART boot image for host as well (used by ART tests)."

This reverts commit e920d2d0.

Reason for revert: b/157053931 - Broken test:
com.android.devicehealthchecks.SystemAppCheck#system_app_native_crash
on git_rvc-dev on crosshatch-userdebug at 6510182

This CL is the only change in this build range so seems likely to be
the culprit.

Build break bug number:
bug:157053931

Original CL bug numbers:
Bug: 147817558
Bug: 147819342
Bug: 156649984

Change-Id: If8bf2f646789b583adcbfbc5df263ce953c05b76