RFR 8249189: AARCH64: more L2I conversions can be skipped (ubfiz)

[Boris Ulasevich]

Hi,

Please review the update for aarch64 AD template file to generate more
bitfield extraction rules where I2L and L2I conversions can be skipped.

http://cr.openjdk.java.net/~bulasevich/8249189/webrev.02
http://bugs.openjdk.java.net/browse/JDK-8249189

Tested with JTREG and manual [1] tests.

thanks,
Boris

[1] 
http://cr.openjdk.java.net/~bulasevich/8249189/webrev.02/TestConversionSkip.java