Improve reproducibility of test runs.

Add random seed to run-tests.py, using either a user supplied
value or a random number generated by random.SystemRandom().
This same random seed is passed to all test cases, making sure
that we can easily reproduce test failures that depend on
random numbers (i.e. bugs related to our handwritten ASLR).

Also fix all uses of rand() to make use of our RNG class
instead.

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/231443002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20637 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Disable concurrent sweeping.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/232413003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20638 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix symmetry of Maybe() predicate. Fix bug in NowContains() predicate.

Add tests for TypeImpl::Of(), TypeImpl::NowOf() and
TypeImpl::NowContains(). Improves the implementation of
TypeImpl::NowIs() to match that of TypeImpl::NowContains().

Mark test-types with NO_VARIANTS to speedup testing, since
the variants do not affect the type system at all.

Also improve test coverage for types.

TEST=cctest/test-types
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/230673002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20639 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Grow small old generation faster.

BUG=
R=bmeurer@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/232593003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20640 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/bleeding_edge' into bleeding_edge