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

This reverts commit 83c9c764b528a7a1c1d39c480d22c8e3a71d5a58.

The tests are shunted to 'pending'.

Whitespace fixes and identifier renaming were not reverted.
Why revert this seemingly innocous commit? 83c9c76 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.

Review by @paulp