use ModeToolBootstrap for compiletest and run-make-support

We don't need to ensure std (and rustc) for running run-make-support
and compiletest unit tests. Using stage 0 compiler is already enough and
speeds up `x test compiletest`/`x test run-make-support` invocations on a
clean build.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

src/bootstrap/src/core/build_steps/test.rs

@@ -678,15 +678,11 @@ impl Step for CompiletestTest {
     /// Runs `cargo test` for compiletest.
     fn run(self, builder: &Builder<'_>) {
         let host = self.host;
-        let compiler = builder.compiler(builder.top_stage, host);
-
-        // We need `ToolStd` for the locally-built sysroot because
-        // compiletest uses unstable features of the `test` crate.
-        builder.ensure(compile::Std::new(compiler, host));
+        let compiler = builder.compiler(0, host);
         let mut cargo = tool::prepare_tool_cargo(
             builder,
             compiler,
-            Mode::ToolStd,
+            Mode::ToolBootstrap,
             host,
             "test",
             "src/tools/compiletest",
@@ -1325,13 +1321,12 @@ impl Step for CrateRunMakeSupport {
     /// Runs `cargo test` for run-make-support.
     fn run(self, builder: &Builder<'_>) {
         let host = self.host;
-        let compiler = builder.compiler(builder.top_stage, host);
+        let compiler = builder.compiler(0, host);
 
-        builder.ensure(compile::Std::new(compiler, host));
         let mut cargo = tool::prepare_tool_cargo(
             builder,
             compiler,
-            Mode::ToolStd,
+            Mode::ToolBootstrap,
             host,
             "test",
             "src/tools/run-make-support",