Fix typo in name of "validation_tests_optimization" config

Change-Id: I93f9db6c75c7e3e528930d3f04d61f3ebb89ffb6
diff --git a/tests/BUILD.gn b/tests/BUILD.gn
index ffb0cee..e102d60 100644
--- a/tests/BUILD.gn
+++ b/tests/BUILD.gn
@@ -74,7 +74,7 @@
     "//third_party/shaderc/third_party/glslang:SPIRV",
     "//third_party/shaderc/third_party/glslang:SPVRemapper",
   ]
-  configs += [ ":validation_tests_optimization "]
+  configs += [ ":validation_tests_optimization" ]
 }
 
 executable("loader_validation_tests") {
@@ -85,7 +85,7 @@
   deps = [
     ":validation_tests_common",
   ]
-  configs += [ ":validation_tests_optimization "]
+  configs += [ ":validation_tests_optimization" ]
 }
 
 executable("layer_validation_tests") {
@@ -99,5 +99,5 @@
   deps = [
     ":validation_tests_common",
   ]
-  configs += [ ":validation_tests_optimization "]
+  configs += [ ":validation_tests_optimization" ]
 }