Update tests-x64.yml

pipelines/Windows/tests-x64.yml

@@ -17,7 +17,7 @@ steps:
 - task: DotNetCoreCLI@2
   inputs:
     command: 'custom'
-    custom: 'workload install wasi-experimental'
+    custom: workload install wasi-experimental
 
 - task: NuGetCommand@2
   inputs: