Revert "RendererVk: Enable VK_KHR_image_format_list on SwiftShader."

This reverts commit 8559d50b3b.

Reason for revert: Causes MSAN failures. See crbug.com/1260941

Original change's description:
> RendererVk: Enable VK_KHR_image_format_list on SwiftShader.
>
> This reverts commit 08b42714f5.
>
> Bug: angleproject:5281
> Bug: chromium:1245774
> Change-Id: I773d95225301ccf3c2807fd2269b6d7da1195a16
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3223679
> Commit-Queue: Lubosz Sarnecki <lubosz.sarnecki@collabora.com>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>

Bug: angleproject:5281
Bug: chromium:1245774
Bug: chromium:1260941
Change-Id: Id6712aed68ed04d2525549ae016594aa05243a5d
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3226312
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -2716,7 +2716,8 @@ void RendererVk::initFeatures(DisplayVk *displayVk,
 
     ANGLE_FEATURE_CONDITION(
         &mFeatures, supportsImageFormatList,
-        ExtensionFound(VK_KHR_IMAGE_FORMAT_LIST_EXTENSION_NAME, deviceExtensionNames));
+        (ExtensionFound(VK_KHR_IMAGE_FORMAT_LIST_EXTENSION_NAME, deviceExtensionNames)) &&
+            !isSwiftShader);
 
     // Feature disabled due to driver bugs:
     //