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)
Status Name Job ID Coverage
  Build
passed build:lib #24153
docker

00:01:24

 
  Test
passed test:lib #24154
docker

00:00:57

 
  Trigger
passed trigger:android

passed trigger:javascript

passed trigger:python