Adds comparisons, labels, branches to arm64

Adds comparisons, labels, branches.

Also adds compare-and-branch, test-and-branch, and
unconditional branch with 26-bit offset instrucitons
to the disassembler and simulator, but not to the
assembler, yet, since they'll require a bit more
work and this CL is getting big.

R=regis@google.com

Committed: https://code.google.com/p/dart/source/detail?r=34993

[regis, 2014-04-11 20:29:21]

LGTM

https://codereview.chromium.org/235363005/diff/20001/runtime/vm/assembler_arm...
File runtime/vm/assembler_arm64.h (right):

https://codereview.chromium.org/235363005/diff/20001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm64.h:671: const int32_t hiimm = ((imm & 0x1ffffc) >> 2)
<< kImm19Shift;
Instead of
(imm & 0x1ffffc) >> 2
I would write
(imm >> 2) & kImm19Mask

[zra, 2014-04-11 20:39:58]

Thanks!

https://codereview.chromium.org/235363005/diff/20001/runtime/vm/assembler_arm...
File runtime/vm/assembler_arm64.h (right):

https://codereview.chromium.org/235363005/diff/20001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm64.h:671: const int32_t hiimm = ((imm & 0x1ffffc) >> 2)
<< kImm19Shift;
On 2014/04/11 20:29:21, regis wrote:
> Instead of
> (imm & 0x1ffffc) >> 2
> I would write
> (imm >> 2) & kImm19Mask

Done.

[zra, 2014-04-11 20:40:16]

Committed patchset #3 manually as r34993 (presubmit successful).