Make internal printing tests compatible with helpers

WorkflowTest and IPrintManagerParametersTest extend BasePrintTest from
CtsPrintTestCases, which means they now try to load a helper when
BasePrintTest.setUp() runs.  Add the helper installer target preparer
and package to their build files so that these can be found as expected.

With UiDevice being removed from BasePrintTest, also move getUiDevice()
over into the internal tests directly so that they can continue using it.

Bug: 153727434
Test: atest PrintSpoolerOutOfProcessTests android.test.IPrintManagerParametersTest
Change-Id: I7ff580c4288c83a69e319ff3668dcb98b11e4f41