Backport the patch for "ensure std for cross-targets".

Previously, doing `x test compiler/*` would fail the build due to missing std.
This change ensures that it is prepared.

Also, add "[ignore]" tags to the failing unit tests to
ignore them during rust oe-selftest.

Upstream-Status: Backport [https://github.com/rust-lang/rust/pull/122205/commits/5aece7fad06baaa745784d118db862b3e3ccf7f8]

Signed-off-by: Yash Shinde <Yash.Shinde@windriver.com>
---
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 4a4497e57db..da8c88dcd41 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -2505,8 +2505,12 @@
         let mode = self.mode;

         // See [field@compile::Std::force_recompile].
-        builder.ensure(compile::Std::force_recompile(compiler, target));
-        builder.ensure(RemoteCopyLibs { compiler, target });
+        builder.ensure(compile::Std::force_recompile(compiler, compiler.host));
+
+        if builder.config.build != target {
+            builder.ensure(compile::Std::force_recompile(compiler, target));
+            builder.ensure(RemoteCopyLibs { compiler, target });
+        }

         // If we're not doing a full bootstrap but we're testing a stage2
         // version of libstd, then what we're actually testing is the libstd