[turbofan] relative_id of splinters and their children.

[turbofan] relative_id of splinters and their children.

A LiveRange is identified by 2 integers: the vreg() of its TopLevel,
which is the virtual register (operand) ID; and a relative_id(), which has
no meaning in the program, but is valuable in debugging or tracing
scenarios.

This change ensures that relative_id is unique even in cases of splinter
ranges and their children.

Committed: https://crrev.com/96c0e6f96b3a4998aa2047951ddf11001d3bea08
Cr-Commit-Position: refs/heads/master@{#30665}

[Mircea Trofin, 2015-09-09 17:41:41]

mtrofin@chromium.org changed reviewers:
+ bmeurer@chromium.org, jarin@chromium.org

[Benedikt Meurer, 2015-09-09 18:51:17]

lgtm

[Mircea Trofin, 2015-09-09 19:32:21]

The CQ bit was checked by mtrofin@chromium.org

[commit-bot: I haz the power, 2015-09-09 19:32:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1318493005/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1318493005/20001

[commit-bot: I haz the power, 2015-09-09 19:34:01]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-09 19:34:23]

Patchset 2 (id:??) landed as
https://crrev.com/96c0e6f96b3a4998aa2047951ddf11001d3bea08
Cr-Commit-Position: refs/heads/master@{#30665}