Fix one and hide the other warnings from core/jni

Most of the warnings are unused parameter from skia functions.
Cherry-picked from AOSP:https://android-review.googlesource.com/#/c/72224/

Change-Id: I9df57718d117c26b96163f751ccb056ca86ac072
Merge "Fix one and hide the other warnings from core/jni" into cm-11.0