[8u] RFR Backport 8167281: IIOMetadataNode bugs in getElementsByTagName and NodeList.item methods

[Elliott Baron]

Hi,

I'd like to request a review to backport 8167281 to 8u.

Original fix:
https://bugs.openjdk.java.net/browse/JDK-8167281
http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/ffba2718d7f6

The original fix did not apply cleanly, but only required a small change 
to the patch context. This is due to 8u using a raw List in the 
getElementsByTagName signature instead of a parameterized List.

8u webrev:
https://cr.openjdk.java.net/~ebaron/jdk8u/JDK-8167281/webrev.00/

Testing: x86_64 build, jdk_tier1, jdk_imageio tests (including new tests)

Thanks,
Elliott