Fix inconsistent equalfuncs.c behavior for FuncCall.funcformat.

Other equalfuncs.c checks on CoercionForm fields use
COMPARE_COERCIONFORM_FIELD (which makes them no-ops),
but commit 40c24bfef neglected to make _equalFuncCall
do likewise.  Fix that.

This is only strictly correct if FuncCall.funcformat has
no semantic effect, instead just determining ruleutils.c
display formatting.  40c24bfef added a couple of checks
in parse analysis that could break that rule; but on closer
inspection, they're redundant, so just take them out again.

Per report from Noah Misch.

Discussion: https://postgr.es/m/20210606063331.GC297923@rfd.leadboat.com

src/backend/parser/parse_func.c

@@ -222,7 +222,6 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 						   agg_order == NIL && agg_filter == NULL &&
 						   !agg_star && !agg_distinct && over == NULL &&
 						   !func_variadic && argnames == NIL &&
-						   funcformat == COERCE_EXPLICIT_CALL &&
 						   list_length(funcname) == 1 &&
 						   (actual_arg_types[0] == RECORDOID ||
 							ISCOMPLEX(actual_arg_types[0])));