Fix test regressions

- Add missing 'negative: ReferenceError' in S7.9_A5.7_T1
- Remove stale 'negative: ReferenceError' in block-local-closure-get-before-initialization
- Remove all tail-call expressions in test/built-ins/Function
- And update code in test/built-ins/Function to simply use 'f()' instead of 'var r = f(); return r'

Fixes #383