pResults was not getting filled in correctly.

As per the spec:

pResults is an array of VkResult typed elements with
swapchainCount entries. Applications that do not
need per-swapchain results can use NULL for pResults.
If non-NULL, each entry in pResults will be set to the VkResult
for presenting the swapchain corresponding to the same index
in pSwapchains.

Bug: b/144766511

Change-Id: I42fcb6d96218d4dbfa60e857226c0aed72e7d8ca
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/38369Reviewed-by: Chris Forbes <chrisforbes@google.com>
Presubmit-Ready: Chris Forbes <chrisforbes@google.com>
Tested-by: Chris Forbes <chrisforbes@google.com>
Tested-by: Andrew Woloszyn <awoloszyn@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>