Fix signature of _emval_as_int64/_emval_as_uint64 in JS. NFC (#19005)

Split out from #18995 since I noticed that it wasn't just the `__sig`
by actually the argument list that was wrong in this case.

Author: sbc100

src/embind/emval.js

@@ -328,15 +328,15 @@ var LibraryEmVal = {
 
   _emval_as_int64__deps: ['$Emval', '$requireRegisteredType'],
   _emval_as_int64__sig: 'jpp',
-  _emval_as_int64: function(handle, returnType, destructorsRef) {
+  _emval_as_int64: function(handle, returnType) {
     handle = Emval.toValue(handle);
     returnType = requireRegisteredType(returnType, 'emval::as');
     return returnType['toWireType'](null, handle);
   },
 
   _emval_as_uint64__deps: ['$Emval', '$requireRegisteredType'],
   _emval_as_uint64__sig: 'jpp',
-  _emval_as_uint64: function(handle, returnType, destructorsRef) {
+  _emval_as_uint64: function(handle, returnType) {
     handle = Emval.toValue(handle);
     returnType = requireRegisteredType(returnType, 'emval::as');
     return returnType['toWireType'](null, handle);