Stop location to avoid timing issue (VTS 2.0)

Before setting constellation blacklist, the location report should
be stopped first. Otherwise, the sv status which contains blacklist
constellation is still reporting and may be counted in checking
SvList. According to the comments of this case, location should be
turned off as 2a step.

Also adding another test that a blacklist request that comes in
while tracking is started, takes effect after a stop/start cycle.

Bug: 144675840
Test: on device
Change-Id: I0a5030cbeeb4bbc45000157414582117d8abbae9