Clean up cc.RegisterRequiredBuildComponentsForTest()

Changes this function so it only registers components from the cc
package by pushing the call to genrule.RegisterGenruleBuildComponents()
down into those packages whose tests need it.

This will make it easier to migrate cc package tests to test fixtures
as the RegisterRequiredBuildComponentsForTest() no longer overlaps with
preparers from the genrule packages.

Bug: 181070625
Test: m nothing
Change-Id: Ic00c7e480dc738d7a88d038aca6ab95a1502a24a