Revert "Vulkan:Adding custom pool allocator"

This reverts commit 941717496141b96f1d5817f31c2bb4a4e19847b9.

Reason for revert: crashes on Debug bots

Original change's description:
> Vulkan:Adding custom pool allocator
> 
> Migrated pool allocator used by compiler to common.
> 
> Planning to use this for ANGLE custom command buffers so this some
> refactoring in preparation for that work.
> 
> Added a unit test to check PoolAllocator functionality.
> 
> Bug: angleproject:2951
> Change-Id: I29618cfdb065b8a5fefd40719a35d27b1f6e99ef
> Reviewed-on: https://chromium-review.googlesource.com/c/1476953
> Reviewed-by: Jamie Madill <jmadill@google.com>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Commit-Queue: Tobin Ehlis <tobine@google.com>

TBR=ynovikov@chromium.org,jmadill@google.com,tobine@google.com,syoussefi@chromium.org

Change-Id: Id8c522bd1d94154e871211d975e801a55cc9c257
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:2951, angleproject:3169
Reviewed-on: https://chromium-review.googlesource.com/c/1487977
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/RendererVk.cpp b/src/libANGLE/renderer/vulkan/RendererVk.cpp
index 2fb8fc8..4589451 100644
--- a/src/libANGLE/renderer/vulkan/RendererVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RendererVk.cpp
@@ -1816,7 +1816,7 @@
     //
     //     Post-submission work             Begin execution
     //
-    //            ????                    Write timestamp Tgpu
+    //            ????                    Write timstamp Tgpu
     //
     //            ????                       End execution
     //