RFR: AArch64: 8134322: Fix several errors in C2 biased locking implementation

[Andrew Dinn]

The following AArch64-only webrev against hs-comp (fix contributed by
Hui Sha of Linaro) fixes several problems with biased locking on AArch64

  http://cr.openjdk.java.net/~adinn/8134322/webrev.00/

I have reviewed the patch. It requires one more AArch64 reviewer who can
also commit it to hs-comp (Andrew Haley?).

When I tested it running netbeans with biased locking enabled it seemed
(just by feel) to improve performance. A follow up to enable biased
locking by default might be worth investigating.

n.b. I built this on hs-comp on top of my (almost but not yet committed)
patch for 8080293 so that patch also gets shown in the webrev. The two
patches are independent and should both commit cleanly with or without
the other.