Revert of Use --icf=all instead of --icf=safe

Revert of Use --icf=all instead of --icf=safe (patchset #2 id:20001 of https://codereview.chromium.org/1153143004/)

Reason for revert:
Speculative, to see if it's related to http://crbug.com/492809

Original issue's description:
> Use --icf=all instead of --icf=safe
>
> With --icf=safe, functions whose address is taken aren't folded.
> Folding could change the results of function pointer comparisons.
>
> However, on x86_64 with pie, --icf=safe disables almost all folding,
> for technical reasons. Since using --icf=all will save 7 MB on x86_64
> and all tests seem to pass with it, switch to --icf=all. If we end up
> having a function where we absolutely need equality, we can pass
> --keep-unique,<symbol-name> for that symbol.
>
> And if this turns out to be some maintenance burden, we can switch
> back to --icf=safe.
>
> Change the flag on all platforms where we use gold, not just x86_64, for
> consistency so that if we end up having problems with this, we notice
> it faster.
>
> BUG=76280, 492177
>
> Committed: https://crrev.com/45ab39af3cc293e150158bf06515a47319db9f79
> Cr-Commit-Position: refs/heads/master@{#331474}

TBR=thestig@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=76280, 492177
Committed: https://crrev.com/9720ab26977ea35252c9ba2e5111c4af63404c22
Cr-Commit-Position: refs/heads/master@{#331724}

[Nico, 2015-05-28 02:24:21]

Created Revert of Use --icf=all instead of --icf=safe

[commit-bot: I haz the power, 2015-05-28 02:25:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1153153003/1

[commit-bot: I haz the power, 2015-05-28 02:26:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-28 02:27:30]

Patchset 1 (id:??) landed as
https://crrev.com/9720ab26977ea35252c9ba2e5111c4af63404c22
Cr-Commit-Position: refs/heads/master@{#331724}

[Lei Zhang, 2015-05-28 05:55:21]

lgtm