[HostStubGen] Remove stub usage in HSG tests

We no longer use the stub functionality in hoststubgen. Before removing
all functionality in the code, we first remove stub usage in tests.

Bug: 292141694
Flag: EXEMPT host test change only
Test: atest hoststubgen-test-tiny-test tiny-framework-dump-test
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: Ib7ca961882fa645c7ca7d026bcb9f569d9f088b0