[embeddingAPI][XWALK-2350] Optimize the embeddingAPI test cases


- Optimize the embeddingAPI test cases according to the latest spec developer privided.
- Change some test methods name to avoid the same id.
- Leverage some cases from unit tests.
- Failure analysis: feature is not supported.

Impacted tests(approved): new 0, update 89, delete 0
Unit test platform: [Android]
Unit test result summary: pass 86, fail 3, block 0