Vulkan: Rename SubAllocation to Suballocation Simply a name change to make it one word. No functional change is expected. Bug: b/205337962 Change-Id: Ic505536821f18141c0d036b13d9aa81554a8bafd Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3403158 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com>