compiletest: require COMPILETEST_FORCE_STAGE0 for ./x test rustdoc-js --stage 0

Author: jieyouxu

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

@@ -1638,10 +1638,7 @@ impl Step for Compiletest {
             return;
         }
 
-        if builder.top_stage == 0
-            && env::var("COMPILETEST_FORCE_STAGE0").is_err()
-            && self.mode != "js-doc-test"
-        {
+        if builder.top_stage == 0 && env::var("COMPILETEST_FORCE_STAGE0").is_err() {
             eprintln!("\
 ERROR: `--stage 0` runs compiletest on the beta compiler, not your local changes, and will almost always cause tests to fail
 HELP: to test the compiler, use `--stage 1` instead