review request (M): 7090968 Allow adlc register class to depend on runtime conditions

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/7090968/webrev.00/

This adds the ability to define reg_class'es in the ad file that, rather than being static, depend on runtime conditions. For the current XXX reg_class, the generated XXX_mask const RegMask declarations are renamed _XXX_mask. XXX_mask inline function definitions are introduced that return _XXX_mask. A new form of reg_class definitions such as:

reg_class some_reg_class %{
	// some C code
%}

is introduced. In this case, the body of the generated inline SOME_REG_CLASS_mask function is defined with the C code present between %{ and %} above.

Tom suggested I used this opportunity to get rid of inline_cache_reg_mask(), interpreter_method_oop_reg_mask(), interpreter_frame_pointer_reg_mask() that are unused. 

Roland.