Address some insufficiency of error handling in the XPath implementation. Some cleanup where appropriate, without attempting to do too much as this is an component that hasn't had much changes for 15 years, a fairly stable application.
------------- Commit messages: - 8284400: Improve XPath exception handling Changes: https://git.openjdk.java.net/jdk/pull/8910/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8910&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8284400 Stats: 861 lines in 11 files changed: 617 ins; 179 del; 65 mod Patch: https://git.openjdk.java.net/jdk/pull/8910.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8910/head:pull/8910 PR: https://git.openjdk.java.net/jdk/pull/8910
