Remove the -t flag

[leighmcculloch]

What

Remove the -t flag.

Why

Newer versions of the singlechecker, which is the library that creates the CLI interface, have a -test=[true|false] option. It's confusing that the CLI interface now has -t and -test.

This change is somewhat problematic to make, because the two flags work contrary to each other. The CLI currently has tests disabled and -t enables them. However, the -test flag works in reverse. Singlechecker assumes tests are enabled by default and -test=false disables them.

Another reason we should remove the -t flag is because it doesn't interact well with the multichecker setup where multiple analyzers are combined together. Analyzers expect tests to be enabled and to let the analysis framework filter tests if flagged.

[leighmcculloch]

This is a breaking change, which may be inconvenient. Should we hold this for a v2? Put it through now because it's in some ways a bug at this point that it's there?