The iOS exec wrapper use the constant bundle id "golang.gotest" for
running Go programs on iOS. However, that only happens to work on
the old iOS builders where their provisioning profile covers
that bundle id.

Expand the detection script to list all available provisioning
profiles for the attached device and include the bundle id in the
GOIOS_APP_ID environment variable.

To allow the old builders to continue, the "golang.gotest" bundle
id is used as a fallback if only the app id prefix is specified in
GOIOS_APP_ID.

For the new builders.

Change-Id: I8baa1d4d57f845de851c3fad3f178e05e9a01b17
Reviewed-on: https://go-review.googlesource.com/36060Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>