[roll] Roll fuchsia [assembly][tests] Add new GN args and top-level groups for separating tests from assembly

This adds a set of GN args that are specifically for adding _tests_ to
build configuration, and not for altering the product / platform being
assembled.

Further, tests are classed by type, and the assertions currently in the
groups will be removed when validattion of tests by type is operational.

hermetic_test_package_labels <- fully hermetic tests
test_pacakge_labels <- non-hermetic at runtime tests
e2e_test_labels <- e2e tests
host_test_labels <- host-only tests, not even emulated

Also added:

developer_test_labels <- tests added by a developer, of any kind.

tests_in_base <- boolean that puts all tests in the hermetic_test_...,
                 developer_test_..., and test_package_labels lists in
                 the base package set of the product being assembled.

These arguments are used to create the following groups:

//:hermetic_test_packages
//:test_packages
//:developer_test_packages
//:e2e_tests
//:host_tests

Two other groups are added, with their deps controlled by tests_in_base:

//:discoverable_tests  (tests are added here when false)
//:bae_tests  (tests are added here when true)

These latter two groups are always deps of the following:

//:discoverable_packages
//:developer_base_packages

which is how they, respectively, are either published  or added to the
assembled product's image.

Original-Bug: b/297219117
Original-Bug: b/297219193
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/906945
Original-Revision: 29dcfa2d63be7ea3072a02350298bfb42b1e21b3
GitOrigin-RevId: 50d4cc7ae2c4ef30f8e28a90ce475efb83547168
Change-Id: Idc5bbce2d4c8caf3f6b6c18b3eb6765a7b48aa4c