setEcho builtin seems broken

[mitchellwrosen]

To reproduce, run the following program:

main : '{Exception, IO} ()
main = do setEcho stdIn true

Result:

Encountered exception:
peekBool: not a boolean
CallStack (from HasCallStack):
  error, called at src/Unison/Runtime/Stack.hs:1184:10 in unison-runtime-0.0.0-EgyIjzCCaNq2oASVOcLwbW:Unison.Runtime.Stack