Revert "Vulkan: Temporarily disable threaded monolithic pipelines."

This reverts commit 69c68ea8d84b8cad4edd54fb81ba3f0d781a9aae.

Reason for revert: Causes more crashes.

Original change's description:
> Vulkan: Temporarily disable threaded monolithic pipelines.
>
> These have a multithreading error. See issue for details.
>
> Bug: angleproject:7369
> Bug: angleproject:7944
> Change-Id: Icbb5e1eb7b026568fa3898d5a94bffd0186fa494
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4153011
> Reviewed-by: Roman Lavrov <romanl@google.com>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

Bug: angleproject:7369
Bug: angleproject:7944
Change-Id: I76f35ee4c405dd634d3c0cbdc98b60e140dbaa55
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4155852
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Jamie Madill <jmadill@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
diff --git a/src/libANGLE/renderer/vulkan/RendererVk.cpp b/src/libANGLE/renderer/vulkan/RendererVk.cpp
index dfdc5c8..b421451 100644
--- a/src/libANGLE/renderer/vulkan/RendererVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RendererVk.cpp
@@ -4265,7 +4265,7 @@
     // VK_EXT_graphics_pipeline_library without graphicsPipelineLibraryFastLinking
     ANGLE_FEATURE_CONDITION(
         &mFeatures, preferMonolithicPipelinesOverLibraries,
-        false /* !mGraphicsPipelineLibraryProperties.graphicsPipelineLibraryFastLinking || isSwiftShader */);
+        !mGraphicsPipelineLibraryProperties.graphicsPipelineLibraryFastLinking || isSwiftShader);
 
     // Whether the pipeline caches should merge into the global pipeline cache.  This should only be
     // enabled on platforms if: