Add a minimal reproducer test-case for issue
#3824

regarding the validation failure of transitive generated
'osgi.extender=osgi.component' requirements in bundles containing DS
components of version 1.4.

(cherry picked from commit 6394de5)

Currently Tycho always uses the INITIAL dependency metadata to compute
the preliminary target platform. As this metadata can change once the
project is packed (e.g. headers added / removed) this can lead to
problems in plugins that depend on the changed plugin because P2 sees
the updated metadata afterwards and fails.

This now distinguish both cases and used the SEED metadata if the
project was already packed.

Fix #3824

(cherry picked from commit fc91332)