RFR: 8214205: PPC64: Add instructions for counting trailing zeros

Dear all, Would you please review the following change that enables POWER9’s instructions for counting trailing zeros? Bug: https://bugs.openjdk.java.net/browse/JDK-8214205 Webrev: http://cr.openjdk.java.net/~mhorie/8214205/webrev.00/ Simple micro benchmark attached showed improvements by around 30%. (See attached file: CNTTZTest.java) Currently, Gustavo@IBM can test POWER9 specific changes. (Thanks Gustavo!) Best regards, -- Michihiro, IBM Research - Tokyo