[torque] Map Torque's JSFunction to V8's JSFunction.

The 'generates' clause was missing (so I suppose it got mapped
to JSReceiver).

Change-Id: I146546921e552f17dbadf74082b31315bf868bf7
Reviewed-on: https://chromium-review.googlesource.com/1032434
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Daniel Clifford <danno@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53093}

src/builtins/base.tq

@@ -25,7 +25,7 @@ type HeapNumber extends HeapObject generates 'TNode<HeapNumber>';
 type Boolean extends Oddball generates 'TNode<Oddball>';
 type JSArray extends HeapObject generates 'TNode<JSArray>';
 type Callable extends JSReceiver generates 'TNode<JSReceiver>';
-type JSFunction extends Callable;
+type JSFunction extends Callable generates 'TNode<JSFunction>';
 type Map extends HeapObject generates 'TNode<Map>';
 type FixedArrayBase extends HeapObject generates 'TNode<FixedArrayBase>';
 type FixedArray extends FixedArrayBase generates 'TNode<FixedArray>';