Remove Context from mockContentResolver to avoid a Null Pointer Exception

mockContentResolver was updated to call a function on the context provided
in its constructor which caused an exception with mockContext. Instead leaving
the context out of the constructor skips this function call and doesn't affect
the test.

Test: Run unit tests with "runtest bluetooth"
Change-Id: I7a597c5864943d3d53dcb551bf3d3bafb4beb5ed