RFR(XS) : 8178340: remove unneeded "throws" from ProcessTools::createJavaProcessBuilder

[Igor Ignatyev]

http://cr.openjdk.java.net/~iignatyev//8178340/webrev.00/index.html
> 8 lines changed: 0 ins; 2 del; 6 mod; 
Hi all,

could you please review this tiny fix which clean up testlibary?

ProcessTools::createJavaProcessBuilder methods can not throw any checked exceptions, but were declared with 'throws Exception', which forced all users of these methods to either have redundant try-catch or throws. the fix cleans up the method declaration in all three copies of testlibary. 

webrev: http://cr.openjdk.java.net/~iignatyev//8178340/webrev.00/index.html
jbs: https://bugs.openjdk.java.net/browse/JDK-8178340
testing: hotspot, jdk, langtools and jaxp tests

Thanks,
-- Igor