Enable host cross python test builds

Ic37c8db918873ddf324c86b12b5412952b0f2be2 converted python_binary_host
and python_library_host from HostSupportedNoCross to HostSupported,
but left python_test_host.  Do the same for python_test_host.

Fixes dependencies between java_test_host modules that create
host cross variants and python_test_host modules that were missing
host cross variants.

Bug: 282918027
Test: builds
Change-Id: Iae687aa3aa0f0b005f2dd27469f631145247a008