fix multiple intersection logic

fix multiple intersection logic

When three or more curves intersect at the same point, ensure that
each curve records the intersections of the others. This fixes a
number of cubic tests.

TBR=reed@google.com
BUG=skia:3588
Committed: https://skia.googlesource.com/skia/+/08bc8488fa2ea2d2a17efb1443f0ec6579d5a3c8

[caryclark, 2015-04-24 15:55:04]

The CQ bit was checked by caryclark@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-04-24 15:55:20]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1105943002/1

[commit-bot: I haz the power, 2015-04-24 16:01:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-24 16:01:15]

Dry run: Try jobs failed on following builders:
  Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-Shared-Trybot on client.skia
(JOB_FAILED,
http://build.chromium.org/p/client.skia/builders/Test-Ubuntu-GCC-GCE-CPU-AVX2...)
  Build-Ubuntu-GCC-Arm7-Debug-Android-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-Arm...)

[caryclark, 2015-04-24 16:02:08]

The CQ bit was checked by caryclark@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-04-24 16:02:25]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1105943002/20001

[commit-bot: I haz the power, 2015-04-24 16:07:30]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-24 16:07:31]

Dry run: This issue passed the CQ dry run.

[caryclark, 2015-04-24 16:08:24]

The CQ bit was checked by caryclark@google.com

[commit-bot: I haz the power, 2015-04-24 16:08:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1105943002/20001

[commit-bot: I haz the power, 2015-04-24 16:09:02]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/08bc8488fa2ea2d2a17efb1443f0ec6579d5a3c8