RFR 8076039: Remove the unused internal API sun.reflect.misc.FieldUtil.getDeclaredFields

[Srikanth]

Greetings,

Please review this patch to remove the said unused internal API - this 
has been
reviewed by a couple of engineers already and is now submitted now for 
wider
review. I have built JDK on all platforms and ran the tests to make sure 
this is safe.

JBS:        https://bugs.openjdk.java.net/browse/JDK-8076039
Webrev: http://cr.openjdk.java.net/~sadayapalam/8076039/webrev/

Thanks!
Srikanth