turnip: do not ignore early_fragment_tests
Reenactment of !9569 (merged)
Specifying "early_fragment_tests" in fragment shader takes precedence over our internal conditions.
Fixes test:
dEQP-VK.fragment_operations.early_fragment.early_fragment_tests_stencil
Fixes: b2a60c15 "turnip: add LRZ early-z support"
CC: @samuelig