Arguably, we don't need a ScopedMinijail for a program that only execs,
but I'd rather keep the code consistent and have all uses of Minijail
be good examples.
Bug: 30156807
Change-Id: I08a968835e0f3e2afcd5e7736626edbed658cde2
We already have to have a Java and a native implementation; we don't
need _two_ native implementations.
Change-Id: I0201205ce5079ef9c747abc37b0c8122cf8fb136