Auto merge of #32755 - alexcrichton:rustbuild-start-test, r=brson

rustbuild: Add support for compiletest test suites

This commit adds support in rustbuild for running all of the compiletest test
suites as part of `make check`. The `compiletest` program was moved to
`src/tools` (like `rustbook` and others) and is now just compiled like any other
old tool. Each test suite has a pretty standard set of dependencies and just
tweaks various parameters to the final compiletest executable.

Note that full support is lacking in terms of:

* Once a test suite has passed, that's not remembered. When a test suite is
  requested to be run, it's always run.
* The arguments to compiletest probably don't work for every possible
  combination of platforms and testing environments just yet. There will likely
  need to be future updates to tweak various pieces here and there.
* Cross compiled test suites probably don't work just yet, support for that will
  come in a follow-up patch.

src/test/compile-fail/regions-bounded-method-type-parameters-cross-crate.rs

@@ -8,11 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// aux-build:regions_bounded_method_type_parameters_cross_crate_lib.rs
+// aux-build:rbmtp_cross_crate_lib.rs
 
 // Check explicit region bounds on methods in the cross crate case.
 
-extern crate regions_bounded_method_type_parameters_cross_crate_lib as lib;
+extern crate rbmtp_cross_crate_lib as lib;
 
 use lib::Inv;
 use lib::MaybeOwned;

src/test/compile-fail/typeck-default-trait-impl-cross-crate-coherence.rs

@@ -8,14 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// aux-build:typeck_default_trait_impl_cross_crate_coherence_lib.rs
+// aux-build:tdticc_coherence_lib.rs
 
 // Test that we do not consider associated types to be sendable without
 // some applicable trait bound (and we don't ICE).
 
 #![feature(optin_builtin_traits)]
 
-extern crate typeck_default_trait_impl_cross_crate_coherence_lib as lib;
+extern crate tdticc_coherence_lib as lib;
 
 use lib::DefaultedTrait;