Use set instead of array to keep list of supported plugins per client

Summary: Use set instead of array to keep list of supported plugins per client. It is not used as array anyway, in most places it is used to determine whether a plugin is supported or not and it's much faster to use set for that.

Reviewed By: priteshrnandgaonkar

Differential Revision: D29200673

fbshipit-source-id: 5f3c404a1a668c153867d7c1b6c223941f0b3b36

desktop/flipper-plugin/src/test-utils/test-utils.tsx

@@ -196,7 +196,7 @@ export function startPlugin<Module extends FlipperPluginModule<any>>(
   const deviceName = 'TestDevice';
   const fakeFlipperClient: RealFlipperClient = {
     id: `${appName}#${testDevice.os}#${deviceName}#${testDevice.serial}`,
-    plugins: [definition.id],
+    plugins: new Set([definition.id]),
     query: {
       app: appName,
       device: deviceName,