Fix #1346: Added test cases ExplorationTestActivity

[rt4914]

Explanation

Fixes #1346

This PR adds some test cases for landscape mode of ExplorationActivity.
The AudioPlayer is a complicated issue and currently does not support orientation change and therefore a separate issue has been filed for that. #1360

NOTE: Run these test cases on real device and if any test case fails on emulator, run it again, it should passes easily.

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
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[veena14cs]

LGTM.