Fix symmetry of Maybe() predicate. Fix bug in NowContains() predicate.

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

Committed: https://code.google.com/p/v8/source/detail?r=20639

[Benedikt Meurer, 2014-04-09 11:52:28]

Work in progress

[rossberg, 2014-04-09 13:59:10]

LGTM

https://codereview.chromium.org/230673002/diff/1/test/cctest/test-types.cc
File test/cctest/test-types.cc (right):

https://codereview.chromium.org/230673002/diff/1/test/cctest/test-types.cc#ne...
test/cctest/test-types.cc:94: size_t i = rand() % types.size();
I thought we shouldn't use rand... :)

[Benedikt Meurer, 2014-04-10 05:19:16]

https://codereview.chromium.org/230673002/diff/1/test/cctest/test-types.cc
File test/cctest/test-types.cc (right):

https://codereview.chromium.org/230673002/diff/1/test/cctest/test-types.cc#ne...
test/cctest/test-types.cc:94: size_t i = rand() % types.size();
Another CL...

[Benedikt Meurer, 2014-04-10 08:04:57]

Committed patchset #5 manually as r20639 (presubmit successful).