Review request: 8004657: Add hooks to javac to enable reporting dependency information.

[Fredrik Öhrström]

These are the minimal changes to javac to enable the smart javac wrapper 
to do its work.
I.e. extract dependency information from javac compiles. It also removes 
two global static
variables that prevents multi core setting of options.

http://cr.openjdk.java.net/~ohrstrom/webrev-8004657-javac_hooks/

//Fredrik