cleanup cctest generally and remove ctest::context

R=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23519010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16831 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Allocation site tests aren't compatible with GcStress mode.

They make assumptions about elementskind of arrays based on allocation site
feedback. This feedback is highly dependent on mementos, unrooted objects
placed behind arrays in the heap meant to live until the next scavenge.

GcStress does many more gcs than normal, and wrecks havoc with this kind
of test.

BUG=
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/23449042

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16832 ce2b1a6d-e550-0410-aec6-3dcde31c8c00