Revert of [heap] More flag cleanup.

Revert of [heap] More flag cleanup. (patchset #8 id:140001 of https://codereview.chromium.org/1314863003/ )

Reason for revert:
Breaks http://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug%20-%202/builds/2372

Original issue's description:
> [heap] GC flag cleanup/restructuring.
>
> * GC's flags are now proper flags and not int.
> * Callback flags are not threaded through but only set once like gc flags
> * Callers of methods that trigger GCs need to pass a reason when not using
>   the default parameters.
>
> Furthermore, each GC invocation can be passed the GC and GCCallback flags. We
> usually override the currently set flags upon finishing a GC cylce, but are able
> to restore the previously set if desired. This is useful for explicitely
> triggered scavenges or external requests that interrupt the current behaviour.
>
> BUG=
>
> Committed: https://crrev.com/f4f3b431b9ce0778d926acf03c0d36dae5c0cba4
> Cr-Commit-Position: refs/heads/master@{#30457}

TBR=hpayer@chromium.org,yangguo@chromium.org,mlippautz@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/6eb837697a2f92c96d9e48c162f7b0391eb16556
Cr-Commit-Position: refs/heads/master@{#30463}

[Michael Hablich, 2015-08-31 10:23:07]

Created Revert of [heap] More flag cleanup.

[commit-bot: I haz the power, 2015-08-31 10:23:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1303393004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1303393004/1

[commit-bot: I haz the power, 2015-08-31 10:23:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-31 10:23:41]

Patchset 1 (id:??) landed as
https://crrev.com/6eb837697a2f92c96d9e48c162f7b0391eb16556
Cr-Commit-Position: refs/heads/master@{#30463}

[Michael Achenbach, 2015-08-31 11:01:29]

machenbach@chromium.org changed reviewers:
+ machenbach@chromium.org

[Michael Achenbach, 2015-08-31 11:01:29]

lgtm