build: improve treeshakeability (#5682)

packages/reactivity/src/baseHandlers.ts

@@ -35,6 +35,7 @@ import { warn } from './warning'
 const isNonTrackableKeys = /*#__PURE__*/ makeMap(`__proto__,__v_isRef,__isVue`)
 
 const builtInSymbols = new Set(
+  /*#__PURE__*/
   Object.getOwnPropertyNames(Symbol)
     .map(key => (Symbol as any)[key])
     .filter(isSymbol)

packages/reactivity/src/deferredComputed.ts

@@ -4,7 +4,7 @@ import { ComputedGetter, ComputedRef } from './computed'
 import { ReactiveFlags, toRaw } from './reactive'
 import { trackRefValue, triggerRefValue } from './ref'
 
-const tick = Promise.resolve()
+const tick = /*#__PURE__*/ Promise.resolve()
 const queue: any[] = []
 let queued = false