Move compiler cctests into v8::internal::compiler namespace.

Move compiler cctests into v8::internal::compiler namespace.

This moves all cctest files for the compiler to live in the same
namespace as the components they are testing. Hence we can avoid the
forbidden using directives pulling in entire namespaces.

From the Google C++ style guide: "You may not use a using-directive to
make all names from a namespace available". This would be covered by
presubmit linter checks if build/namespaces were not blacklisted.

R=bmeurer@chromium.org

Committed: https://crrev.com/16f133001f3370ea7b8e6ee92b6827e67a14dd38
Cr-Commit-Position: refs/heads/master@{#31671}

[Benedikt Meurer, 2015-10-30 04:44:16]

LGTM

[Michael Starzinger, 2015-10-30 09:06:16]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-10-30 09:06:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1424943004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1424943004/1

[commit-bot: I haz the power, 2015-10-30 09:16:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-30 09:16:47]

Patchset 1 (id:??) landed as
https://crrev.com/16f133001f3370ea7b8e6ee92b6827e67a14dd38
Cr-Commit-Position: refs/heads/master@{#31671}