Deno panics when called from a non-existent directory.

[andre4ik3]

Description:

When Deno is called from a directory that used to exist but doesn't anymore (i.e. deleted externally), it will panic.

Steps to Reproduce:

1. mkdir /tmp/testing && cd /tmp/testing
2. deno or deno repl or deno run https://deno.land/std/examples/welcome.ts
3. Observe that it works

-in another terminal-

rm -rf /tmp/testing

-back to the original terminal-

4. Re-run the command.
5. Observe panic.

Backtrace: backtrace.txt

[cjihrig]

Closing as a duplicate of #14868.