Changes to Tapir intrinsics

[VoxSciurorum]

Updates to intrinsics and attributes in preparation for passing the frame to the runtime when looking up a view.

1. Remove HyperToken. This was an idea I had for implementing reducers. It was never completed.

2. New builtin __tapir_frame. This returns the stack frame object in an OpenCilk object that has one, otherwise null.

3. A new, more precise memory use attribute for functions that only read inaccessible memory.