[14] RFR (S): 8234387: C2: Better support of operands with multiple match rules in AD files

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/jbhateja/8234387/webrev.00
https://bugs.openjdk.java.net/browse/JDK-8234387

Though ADLC accepts operands with multiple match rules, it doesn't 
generate correct code to handle them except the first one.

It doesn't cause any noticeable problems for existing code, but is a 
major limitation for generic vector operands (JDK-8234391 [1]).

Proposed fix enumerates all match rules.

Fixed some missing declarations along the way.

Contributed-by: Jatin Bhateja <jatin.bhateja at intel.com>
Reviewed-by: vlivanov, sviswanathan, ?

Testing: tier1-4 (both with and without generic vectors)

Best regards,
Vladimir Ivanov

[1] https://bugs.openjdk.java.net/browse/JDK-8234391