Summary:
This commit is the result of
`find infer/src -name '*.ml' -or -name '*.mli' -exec ocp-indent -i \{\} \;`
and
`INFER_CHECK_COPYRIGHT=1 InferPrint`
Summary:
Treat `arrayWithObjects` as a special case of a sentinel attribute check. This
will make it easier to extend to other variadic functions that use a sentinel
attribute.
This also removes the need for the `Sil.Avariadic_function_argument` attribute,
which will be removed in a subsequent diff.