RFR: 8164483: Generate field lambda forms at link time

[Claes Redestad]

Hi,

this patch adds link-time generation of the simplest field lambda forms. 
This avoid generating these forms during bootstrapping, which is 
commonly done early on in even the simplest startup tests.

To make this work, injecting Unsafe as a constant replacement had to be 
replaced with a getter function, resulting in a few more bytecodes to do 
the same thing, but which after inlining should turn into equivalent 
code; performance testing indicate this change is performance neutral.

Bug: https://bugs.openjdk.java.net/browse/JDK-8164483
Webrev: http://cr.openjdk.java.net/~redestad/8164483/webrev.01/

Together with JDK-8164569 (which I've tested together with this) this 
removes all class generation from runtime in the tests associated with 
JDK-8086045

Thanks!

/Claes