Move bootstrap tests to the end of the default test run

Since they are unlikely to fail and are almost never going to fail
except with bootstrap changes (which would be tested locally anyway) it
makes sense to run these tests close to last.

src/bootstrap/builder.rs

@@ -370,7 +370,6 @@ impl<'a> Builder<'a> {
             ),
             Kind::Test => describe!(
                 test::Tidy,
-                test::Bootstrap,
                 test::Ui,
                 test::RunPass,
                 test::CompileFail,
@@ -416,6 +415,8 @@ impl<'a> Builder<'a> {
                 test::Clippy,
                 test::RustdocJS,
                 test::RustdocTheme,
+                // Run bootstrap close to the end as it's unlikely to fail
+                test::Bootstrap,
                 // Run run-make last, since these won't pass without make on Windows
                 test::RunMake,
                 test::RustdocUi