Migrate run-make/rustdoc-target-spec-json-path to rmake

Author: GuillaumeGomez

Diff for: src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -251,7 +251,6 @@ run-make/rustdoc-scrape-examples-multiple/Makefile
 run-make/rustdoc-scrape-examples-remap/Makefile
 run-make/rustdoc-scrape-examples-test/Makefile
 run-make/rustdoc-scrape-examples-whitespace/Makefile
-run-make/rustdoc-target-spec-json-path/Makefile
 run-make/rustdoc-themes/Makefile
 run-make/rustdoc-verify-output-files/Makefile
 run-make/rustdoc-with-out-dir-option/Makefile

Diff for: tests/run-make/rustdoc-target-spec-json-path/Makefile

@@ -0,0 +1,14 @@
+// Test that rustdoc will properly canonicalize the target spec json path just like rustc.
+
+use run_make_support::{rustc, rustdoc, tmp_dir};
+
+fn main() {
+    let out_dir = tmp_dir().join("rustdoc-target-spec-json-path");
+    rustc().crate_type("lib").input("dummy_core.rs").target("target.json").run();
+    rustdoc()
+        .input("my_crate.rs")
+        .output(out_dir)
+        .library_search_path(tmp_dir())
+        .target("target.json")
+        .run();
+}