[Android] Add WebCL conformance test suites.

Include WebCL conformance test suites from upstream
(https://github.com/KhronosGroup/WebCL-conformance)
in the Crosswalk DEPS. It's used for tracking WebCL
API implementation following the spec, supposed to
integrate into buildbot for auto verification in
future.

It contains bindingTesting, extension, functionalityTesting
and security four components.

BUG=XWALK-2552