Fix up-to-date checking for run-make tests

This special case in `output_base_dir` had the unfortunate side-effect of
causing all run-make tests to share the same `stamp` file. So as soon as any
one of them succeeded, all of the failed tests would be considered up-to-date
and would no longer run in subsequent test invocations.

src/tools/compiletest/src/common.rs

@@ -759,14 +759,8 @@ pub fn output_testname_unique(
 /// test/revision should reside. Example:
 ///   /path/to/build/host-triple/test/ui/relative/testname.revision.mode/
 pub fn output_base_dir(config: &Config, testpaths: &TestPaths, revision: Option<&str>) -> PathBuf {
-    // In run-make tests, constructing a relative path + unique testname causes a double layering
-    // since revisions are not supported, causing unnecessary nesting.
-    if config.mode == Mode::RunMake {
-        output_relative_path(config, &testpaths.relative_dir)
-    } else {
-        output_relative_path(config, &testpaths.relative_dir)
-            .join(output_testname_unique(config, testpaths, revision))
-    }
+    output_relative_path(config, &testpaths.relative_dir)
+        .join(output_testname_unique(config, testpaths, revision))
 }
 
 /// Absolute path to the base filename used as output for the given

tests/run-make/README.md

@@ -29,7 +29,7 @@ The setup for the `rmake.rs` version is a 3-stage process:
    structure within `build/<target>/test/run-make/`
 
    ```
-   <test-name>/
+   <test-name>/<test-name>/
        rmake.exe              # recipe binary
        rmake_out/             # sources from test sources copied over
    ```