We are generating the caps map using various bits from the results of
vkGetPhysicalDeviceFormatProperties. This contains all the information
required to fill out "renderable", "texturable" and "filterable".

Later we'll need to read from vkGetPhysicalDeviceImageFormatProperties as
well to get the sampleCounts.

The tests for now are not very meaningful since they use the same logic
as the caps code to build the expected results, however as soon as we'll
add the hard-coded list of mandatory texture caps, the test will be a good
validator that we are not breaking anything.

We only check the optimal set of flags since it is the most restrictive
set.

isTexturable = flags contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT
isFilterable = flags contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT
isRenderable = flags contain VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT OR
			     VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT

Bug: angleproject:2348

Change-Id: I9da0712190d2678d7e377d6fcd4ca83d23eefd38
Reviewed-on: https://chromium-review.googlesource.com/908712
Commit-Queue: Luc Ferron <lucferron@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>