When VK_EXT_LINE_RASTERIZATION or VK_EXT_PROVOKING_VERTEX is present,
createInfo's pNext pointer is set, which caused pEnabledFeatures to
not be set, which ended up causing memory corruption issues.

This change was made to comply with the Vulkan spec, specifically:
"If the pNext chain includes a VkPhysicalDeviceFeatures2 structure,
 then pEnabledFeatures must be NULL"

Since the VkPhysicalDeviceFeatures2 structure is only added to the
pNext member of the createInfo structure in the if statement above,
restoring the else statement solves this issue.

Bug: angleproject:4060
Change-Id: I0688c4297f167fa28e110cd6ee11a11b95282493
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1899731Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tobin Ehlis <tobine@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>