RFR(S): 8034087: XML parser may overwrite element content if that content falls onto the border of an entity scanner buffer

[Volker Simonis]

Hi,

after opening this bug yesterday for an issue found by my colleague
Steffen Schreiber we realized that this is actually a duplicate of
"8027359: XML parser returns incorrect parsing results"
(https://bugs.openjdk.java.net/browse/JDK-8027359).

While there's no need now to submit a patch anymore,  we'd
nevertheless like to contribute at least our test case for this issue:

http://cr.openjdk.java.net/~simonis/webrevs/8034087/

The webrev is against jdk9-client but we'd like to also downport this
test to jdk7 and jdk8 to track that the fix for 8027359 will be
correctly downported to these releases as well.

I will sponsor this change if somebody would be so kind to review it.

Thank you and best regards,
Volker