[dfmc] Remove remnants of flow-typist.

This removes code that was part of the flow-typist project which
was removed long ago.

This includes call-site-summary (css) and some alternative
typist entry points such as lookup-type and type-initializer-method.
Merge pull request #776 from waywardmonkeys/cleanup-flow-typist-remnants

[dfmc] Remove remnants of flow-typist.
Proofread looks good.