Update SPIRV-Tools version

Pulls in fix for nontemporal operand

Components: Framework

Change-Id: I248f7c12094d318682cc80e82db2a876f2aa4634
diff --git a/external/fetch_sources.py b/external/fetch_sources.py
index 6a3b244..e0f2a34 100644
--- a/external/fetch_sources.py
+++ b/external/fetch_sources.py
@@ -317,7 +317,7 @@
 	GitRepo(
 		"https://github.com/KhronosGroup/SPIRV-Tools.git",
 		None,
-		"a73e724359a274d7cf4f4248eba5be1e7764fbfd",
+		"20b122b2e0d43fcc322a383354d1a3f4514e3757",
 		"spirv-tools"),
 	GitRepo(
 		"https://github.com/KhronosGroup/glslang.git",