copy, pop, get, getitem, setdefault
Also add read steps to taint tracking.
Reading from a tainted collection can be done in two situations:
1. There is an acces path
In this case a read step (possibly from a flow summary)
gives rise to a taint step.
2. There is no access path
In this case an explicit taint step (possibly via a flow
summary) should exist.
note how the test file is partially annotated
and those annotations can now be expressed
In this particular test file, absolute line numbers
might have been better than relative ones.
We might remove line numbers altogether,
but should check more querries to see how it looks.
It's really hard to audit that this is all good.. I tried my best with
`icdiff` though -- and there is a problem with
ql/src/experimental/Security/CWE-348/ClientSuppliedIpUsedInSecurityCheck.ql
that needs to be fixed in the next commit
We were mixing between things, so this is just to keep things
consistent. Even though it's not strictly needed for all queries,
it does look nice I think
