Remove hint from WebCLContextProperties in all Layout Tests.
Issue #97

Reviewed by: Afonso Costa

The hint variable was removed from WebCL specification. Also removed all
shareGroup remaining in LayoutTests, issue #228 from SRA, shareGroup
was removed from specification as well.

Signed-off-by: Marcelo Morais <m.morais@samsung.com>

* webcl/resources/webcl-proxy.js
* webcl/resources/webcl-test.js
* webcl/stress/webcl-stress-buffer.html
* webcl/stress/webcl-stress-context.html
* webcl/stress/webcl-stress-event.html
* webcl/stress/webcl-stress-image.html
* webcl/stress/webcl-stress-kernels-one-device.html
* webcl/stress/webcl-stress-nkernels.html
* webcl/stress/webcl-stress-program.html
* webcl/stress/webcl-stress-queue.html
* webcl/stress/webcl-stress-sampler.html
* webcl/tests/webcl-test-devices-sharing-single-context.html
* webcl/tests/webcl-test-gl-extension-instanceof.html
* webcl/tests/webcl-test-instanceof.html
* webcl/tests/webcl-test-resource-management.html