The root cause of #1218 is that `invokePartial` creates a stack of data frames
for nested partial blocks, but `resolvePartial` always uses the value at top of
the stack without "popping" it. The result is an infinite recursive loop, as
references to `@partial-block` in the partial at the top of the stack resolve to
itself.
So, walk up the stack of data frames when evaluating. This is accomplished by
1) setting the `partial-block` property to `noop` after use and
2) using `_parent['partial-block']` if `partial-block` is `noop`
Fix#1218
Lon Ingram
bbe0a94d6e