Putting "simulator" in the -target flag requires putting it in the
"environment" part of the triple, which is the 4th --separated component.
Some places in the tests currently use "iossimulator" which puts it in the
OS field. The triple parsing code in llvm::Triple uses startswith("ios")
in parseOS(), so that successfully sets the OS to "iOS", and all these
triples use an intel arch, and iOS + intel triple implicitly make the
driver convert the environment to "simulator", so this happened to work --
but it led to the somewhat strange "simulator-simulator" in the diag
in the test.
No behavior change.