Advise against removing the remaining Python scripts from tests/run-make

tests/run-make/debugger-visualizer-dep-info/main.rs

@@ -1,4 +1,4 @@
-#![debugger_visualizer(gdb_script_file = "foo.py")]
+#![debugger_visualizer(gdb_script_file = "my_gdb_script.py")]
 
 fn main() {
     const _UNUSED: u32 = {

tests/run-make/debugger-visualizer-dep-info/my_gdb_script.py

@@ -0,0 +1,6 @@
+# This is a Python script, but we don't actually run it.
+# So if you're trying to remove Python scripts from the test suite,
+# be aware that there's no value in trying to get rid of this one.
+#
+# It just needs to exist so that the compiler can embed it via
+# `#![debugger_visualizer(gdb_script_file = "...")]`.

tests/run-make/debugger-visualizer-dep-info/rmake.rs

@@ -6,6 +6,6 @@ use run_make_support::{invalid_utf8_contains, rustc};
 
 fn main() {
     rustc().emit("dep-info").input("main.rs").run();
-    invalid_utf8_contains("main.d", "foo.py");
+    invalid_utf8_contains("main.d", "my_gdb_script.py");
     invalid_utf8_contains("main.d", "my_visualizers/bar.natvis");
 }

tests/run-make/libtest-junit/validate_junit.py

@@ -1,5 +1,15 @@
 #!/usr/bin/env python
 
+# Trivial Python script that reads lines from stdin, and checks that each line
+# is a well-formed XML document.
+#
+# This takes advantage of the fact that Python has a built-in XML parser,
+# whereas doing the same check in Rust would require us to pull in an XML
+# crate just for this relatively-minor test.
+#
+# If you're trying to remove Python scripts from the test suite, think twice
+# before removing this one. You could do so, but it's probably not worth it.
+
 import sys
 import xml.etree.ElementTree as ET