RFR: Several aarch64-related C1 fixes

[Roman Kennke]

1. The write-barrier stub must bind the entry and branch back to
continuation
2. The mask in the WB LIR needs an extra register, otherwise it won't
compile in aarch64
3. bonus: handle both 2- and 3-arg for of logical_and()

http://cr.openjdk.java.net/~rkennke/aarch64-c1fixes/webrev.01/

Testing: some hello-world-ish programs on aarch64. tests are not running yet

Ok?

Roman