[Auto-roll] Bump up version to 3.28.70.0

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/466603002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23062 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Disable code generation in tests that use GraphBuilderTester on platforms that have no TF backend.

R=bmeurer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/457343003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23066 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Assume signed for converting to word32/float64 unless use or output is explicitly unsigned.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/461653002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23067 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Initial import of ChangeLowering.

ChangeLowering is a Reducer to lower simplified change operators
to machine subgraphs. This initial version supports ChangeBitToBool,
ChangeBoolToBit, ChangeTaggedToFloat64 and ChangeInt32ToTagged.

TEST=compiler-unittests/change-lowering-unittest
BUG=v8:3489
LOG=n
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/460593003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23068 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix windows build.

TBR=jarin@chromium.org

Review URL: https://codereview.chromium.org/464773002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23069 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge pull request #1 from v8/master

merge upstream