RFR (JDK10/JAXP) 8181155: Fix lint warnings in JAXP repo: fallthrough and static

[Joe Wang]

Hi,

Please review a cleanup of fallthrough and static warnings. For 
fallthrough, the majority of the changes are suppressing the warnings, 
while for static, replacing the instances with the class.

All jaxp tests and JCK passed.

JBS: https://bugs.openjdk.java.net/browse/JDK-8181155
webrevs: http://cr.openjdk.java.net/~joehw/jdk10/8181155/webrev/index.html

Thanks,
Joe