Move JNI annotations to annotations package.
The rest of the annotations already live in this package,
so this CL moves CalledByNative, NativeCall, JNIAdditionalImport,
NativeClassQualifiedName and JNINamespace to the same package.
BUG=None
TBR=armansito@chromium.org,asvitkine@chromium.org,atwilson@chromium.org,avayvod@chromium.org,bauerb@chromium.org,boliu@chromium.org,brettw@chromium.org,dtrainor@chromium.org,gunsch@chromium.org,lambroslambrou@chromium.org,mef@chromium.org,mnaganov@chromium.org,mnissler@chromium.org,peter@chromium.org,qinmin@chromium.org,sky@chromium.org,yfriedman@chromium.org,yukawa@chromium.org,zea@chromium.org
Review URL: https://codereview.chromium.org/1263053002
Cr-Commit-Position: refs/heads/master@{#341175}
ca3b803930