travis: Add builders without assertions

This commit adds three new builders, one OSX, one Linux, and one MSVC, which
will produce "nightlies" with LLVM assertions disabled. Currently all nightly
releases have LLVM assertions enabled to catch bugs before they reach the
beta/stable channels. The beta/stable channels, however, do not have LLVM
assertions enabled.

Unfortunately though projects like Servo are stuck on nightlies for the near
future at least and are also suffering very long compile times. The purpose of
this commit is to provide artifacts to these projects which are not distributed
through normal channels (e.g. rustup) but are provided for developers to use
locally if need be.

Logistically these builds will all be uploaded to `rustc-builds-alt` instead of
the `rustc-builds` folder of the `rust-lang-ci` bucket. These builds will stay
there forever (until cleaned out if necessary) and there are no plans to
integrate this with rustup and/or the official release process.

0 files changed, 0 insertions, 0 deletions