Fail when an unpickle succeeds but has extra junk data at the end.

Also adds tests to ensure this is working.
5 jobs for dkasak/fix-unpickling-error-handling in 2 minutes and 22 seconds (queued for 11 seconds)
latest
Status Job ID Name Coverage
  Build
passed #24153
docker
build:lib

00:01:24

 
  Test
passed #24154
docker
test:lib

00:00:57

 
  Trigger
passed trigger:android

passed trigger:javascript

passed trigger:python