[webapi][XWALK-1745] Add 1 test, update 1 test and change another one to...

... designed

Add 1 test Speech_setCBListener_exist to test the existence of setCBListener;
Update 1 usage test Speech.html by using API directly instead of the old "MediaPlayer" widget which removed from elf image.
Move 1 test SpeechRecognition_constructor.html to "designed" since web speech API was not supported yet.

TestResult: 3 Pass, 1 Fail
Signed-off-by: Hao yunfeix <yunfeix.hao@intel.com>
Example seems to be better a use-case test.

Another, this is manual test, please add '-manual' suffix to the file name; please also follow the latest test template, `tools/template/reftest_test_case.html`