SI-7516 Revert "SI-7234 Make named args play nice w. depmet types"

This reverts commit 83c9c764b528a7a1c1d39c480d22c8e3a71d5a58.

The tests are shunted to 'pending'.

Why revert this seemingly innocous commit? 83c9c764 generates a ValDef whose
tpt TypeTree has no original; this contains a reference to the symbol for `d`.
resetAttrs and the retypecheck assigns a new symbol for d and leaves a the
reference to the prior symbol dangling. The real bug is the resetAttrs concept.