Close class resource InputStream in ThrowawayClassLoader

[junhyeong9812]

Overview

ThrowawayClassLoader#loadClassFromResource opens an InputStream via
getResourceAsStream(...) but never closes it. The stream leaks on both the
success path (after defineClass) and the IOException path, since the
surrounding try block has neither a finally nor a try-with-resources.

InputStream inputStream = this.resourceLoader.getResourceAsStream(resourceName);
if (inputStream == null) {
    return null;
}
try {
    ...
    return defineClass(name, bytes, 0, bytes.length); // stream never closed
}
catch (IOException ex) {
    throw new ClassNotFoundException(...);             // stream never closed
}

Fix

Adopt the existing inputStream variable as a try-with-resources resource so it
is closed on every path, leaving the loading logic unchanged:

try (inputStream) {
    ...
}

A regression test (ThrowawayClassLoaderTests) verifies the stream is closed by
routing a tracked InputStream through the resource fallback path.

[sbrannen]

This has been merged into main.

Thanks

[junhyeong9812]

Thanks for the review and merge, @sbrannen! I opened #36938 for the related ClassNotFoundException behavior I noticed while working on this — happy to take it further if it's worth pursuing