Vulkan: Fix variable scope bug during vkCreateInstance While enabling best practices layer the struct that gets added to the pNext chain is a stack variable and goes out of scope beyond the if-check. Move the struct variables out of local scope to prevent access violation errors during vkCreateInstance. Bug: b/156661359 Change-Id: Ifa470ff1e51d454782695adcf40b4db2aa1608a0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2335747 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Mohan Maiya <m.maiya@samsung.com>