PPC: [debugger] simplify debug stepping.

PPC: [debugger] simplify debug stepping.

Port 3e2d60d853cdfe49d4db0040b51f75b214a01714

R=yangguo@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/85bef2377483018307d0be22e7004dc034475715
Cr-Commit-Position: refs/heads/master@{#37007}

[JaideepBajwa, 2016-06-15 12:10:57]

PTAL

[john.yan, 2016-06-15 13:01:44]

lgtm

[JaideepBajwa, 2016-06-15 13:05:17]

The CQ bit was checked by bjaideep@ca.ibm.com

[commit-bot: I haz the power, 2016-06-15 13:05:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2065423002/1

[commit-bot: I haz the power, 2016-06-15 13:45:49]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-15 13:45:52]

CQ bit was unchecked

[commit-bot: I haz the power, 2016-06-15 13:47:23]

Description was changed from

==========
PPC: [debugger] simplify debug stepping.

Port 3e2d60d853cdfe49d4db0040b51f75b214a01714

R=yangguo@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N
==========

to

==========
PPC: [debugger] simplify debug stepping.

Port 3e2d60d853cdfe49d4db0040b51f75b214a01714

R=yangguo@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/85bef2377483018307d0be22e7004dc034475715
Cr-Commit-Position: refs/heads/master@{#37007}
==========

[commit-bot: I haz the power, 2016-06-15 13:47:24]

Patchset 1 (id:??) landed as
https://crrev.com/85bef2377483018307d0be22e7004dc034475715
Cr-Commit-Position: refs/heads/master@{#37007}