Fix library method argument references (#8252)

Each VCMethod now carries a signature describing the access required of
the references passed as arguments to the call. 'r' if the argument is
read, 'w' if it is fully assigned so the old value does not matter, 'm'
if it is modified (or only conditionally assigned), with a trailing '+'
repeating the preceding entry for all remaining arguments.  Signatures
are validated at compile time, and V3Broken checks the arguments of
every AstCMethodHard against them.

The incorrect references this found and that are easy to fix are
repaired in this patch. "TODO" marks method that are currently broken or
not yet fit the scheme, these will be fixed in follow up patches.

Also renames SCHED_COMMIT and SCHED_ENQUEUE to NBA_COMMIT and
NBA_ENQUEUE, and remove unused methods.

src/V3AssertPre.cpp

@@ -414,6 +414,7 @@ private:
                     flp, new AstVarRef{flp, queueVarp, VAccess::READWRITE}, VCMethod::DYN_POP,
                     new AstTime{nodep->fileline(), m_modp->timeunit()}};
                 popp->addPinsp(skewp->unlinkFrBack());
+                refp->access(VAccess::READWRITE);  // Only conditionally assigned
                 popp->addPinsp(refp);
                 popp->dtypeSetVoid();
                 m_clockingp->addNextHere(