added

Add logic to invalidate any packages with missing dependencies when a
file is added.

Also fix a latent bug overwriting 'anyFileOpenenedOrClosed' for each
loop iteration.

Fixes golang/go#54073

Change-Id: I000ceb354885bd4863a1dfdda09e4d5f0e5481f3
Reviewed-on: https://go-review.googlesource.com/c/tools/+/419501
Run-TryBot: Robert Findley <[email protected]>
Reviewed-by: Suzy Mueller <[email protected]>
gopls-CI: kokoro <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>