[foreign] RFR: 8224244: Cleanup libclang Java API

[Henry Jen]

Hi,

Please review the webrev[1] for clang Java API cleanup that came up with earlier work on atomic type support.
Mainly to throw a checked exception on parsing error, and move translation unit APIs into TranslationUnit class.

Cheers,
Henry

[1] http://cr.openjdk.java.net/~henryjen/panama/8224244/0/webrev/
[2] https://bugs.openjdk.java.net/browse/JDK-8224244