Move a simple utility method from `URL` to the shared `sun.net.util.URLUtil` class, rename it for clarity and enhance it so that it returns a string literal. This helps reduce dependencies from bootstrap code on `Locale` while improving the performance and allocation pressure in certain applications.
------------- Commit messages: - Use URLUtil.lowerCaseProtocol in URLConnection - 8294626: Improve URL protocol lower casing Changes: https://git.openjdk.org/jdk/pull/10506/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10506&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8294626 Stats: 42 lines in 3 files changed: 21 ins; 14 del; 7 mod Patch: https://git.openjdk.org/jdk/pull/10506.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10506/head:pull/10506 PR: https://git.openjdk.org/jdk/pull/10506
