[xwalk-2832] create a case to test to call bluetooth.getDefaultAdapter()...

Impacted tests: new 1, update 0, delete 0
Unit test platform: [IVI] crosswalk-10.38.222, t-e-c 0.107
Unit test result summary: pass 0, fail 1, block 0
In https://github.com/cybibo/crosswalk-test-suite/blob/xwalk-2832-misc-system/misc/xwalk-system-tests/suite.json, this block isn't correct. Please check with @jiajiax . Sub-app should not include the *.xml files.

Please use 'tools/format/json_formatter' to format the json file.

```
 "wgt": {
"subapp-list":{
"bluetoothgetdefaultadapter-tests": {
"app-dir": ".",
"app-name": "bluetoothgetdefaultadapter-tests",
"blacklist": [],
"copylist": {
"inst.wgt.py": "inst.py",
"tests.full.xml": "tests.full.xml",
"tests.tizen.xml": "tests.xml"
}
"pkg-app": {
"blacklist": [],
"sign-flag": "true"
}
}
}
},
```