Fill some gaps in the ANGLE end2end instanced draw test.
The only testing of points was on D3D11 and D3D11_FL9_3.
There was little testing of number of instances and different divisors.

Remove old one-off tests which are now redundant.

Disable the D3D11_FL9_3 points test which was passing purely by chance.
That code has bugs and only supports data from a buffer, while the
test uses data in client memory.

BUG=angleproject:2672

Change-Id: I5b5707a6fdd0960e81c25a2eb8ed96a1452d9868
Reviewed-on: https://chromium-review.googlesource.com/c/1450789
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>