These occur when persp-mode is active, but a frame is created with
after-make-frame-functions bypassed (i.e., let-bound to nil), resulting in
frames without frame parameters which persp-mode expects.

Since most of these errors occur in unguarded use of perspectives-hash,
persp-curr, and persp-last, this workaround tries to return reasonable but empty
values from these functions instead of nil.