Review Request: JDK-8176815: Remove StackFramePermission and use RuntimePermission for stack walking

StackWalker::getInstance is currently specified to check for StackFramePermission("retainClassReference“) due to an early review feedback . Given it has only one target, it’s overkill to define a specific permission type for stack walking use. This patch proposes to replace the StackWalker permission check with RuntimePermission("getStackWalkerWithClassReference”) and remove StackFramePermission class. http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8176815/webrev.00/ Mandy