SecurityManager being mutable impedes the optimization of Class.getClassLoader

Class.getClassLoader() can't be trivially intrinsified because of the SecurityManager.

This issue is to track the idea that Christian Thalinger has (see JDK-6642881) to replace the System.security field with a VolatileCallSite. Combined with intrinsification of Class.getClassLoader() (or better moving the class loader field up into Java) we could constant fold two security related checks.

Attachd patch [1] is not working properly yet because of bootstrapping issues but the idea is that CallSite optimizations in the JIT compilers can constant fold the System.getSecurityManager() call.

[1] https://bugs.openjdk.java.net/secure/attachment/18729/system-getsecuritymanager.patch