PPC: Debugger: record reloc info for debug break slot immediate before the slot.

PPC: Debugger: record reloc info for debug break slot immediate before the slot.

Port 0a19e44925301b9c0a554bbec5e3fb5a6cd09efa

Original commit message:
    If we do it too early, we might get a constant pool between the reloc info
    and the actual slot.

R=yangguo@chromium.org, dstence@us.ibm.com, michael_dawson@ca.ibm.com
BUG=

Committed: https://crrev.com/f91119c4554bdf30facb36fca0558d18e4589faf
Cr-Commit-Position: refs/heads/master@{#29585}

[dstence, 2015-07-10 20:53:38]

lgtm

[MTBrandyberry, 2015-07-10 20:55:35]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-07-10 20:55:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1232123006/1

[commit-bot: I haz the power, 2015-07-10 20:57:02]

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

[commit-bot: I haz the power, 2015-07-10 20:57:03]

Try jobs failed on following builders:
  v8_linux64_avx2_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel/builds/...)
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/7542)
  v8_linux_mipsel_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_rel...)
  v8_win_nosnap_shared_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_nosnap_shared_compil...)

(exceeded global retry quota)

[MTBrandyberry, 2015-07-10 21:04:21]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-07-10 21:04:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1232123006/1

[commit-bot: I haz the power, 2015-07-10 21:27:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-10 21:27:54]

Patchset 1 (id:??) landed as
https://crrev.com/f91119c4554bdf30facb36fca0558d18e4589faf
Cr-Commit-Position: refs/heads/master@{#29585}