Remove useless optimisation (#736)

.size-snapshot.json

@@ -1,18 +1,18 @@
 {
   "lib/packages/recompose/dist/Recompose.umd.js": {
-    "bundled": 46995,
-    "minified": 16584,
-    "gzipped": 4651
+    "bundled": 46555,
+    "minified": 16485,
+    "gzipped": 4623
   },
   "lib/packages/recompose/dist/Recompose.min.js": {
-    "bundled": 43433,
-    "minified": 15304,
-    "gzipped": 4220
+    "bundled": 42993,
+    "minified": 15205,
+    "gzipped": 4193
   },
   "lib/packages/recompose/dist/Recompose.esm.js": {
-    "bundled": 31320,
-    "minified": 14839,
-    "gzipped": 3451,
+    "bundled": 30894,
+    "minified": 14729,
+    "gzipped": 3417,
     "treeshaked": {
       "rollup": {
         "code": 340,

src/packages/recompose/withStateHandlers.js

@@ -1,7 +1,6 @@
 import { createFactory, Component } from 'react'
 import setDisplayName from './setDisplayName'
 import wrapDisplayName from './wrapDisplayName'
-import shallowEqual from './shallowEqual'
 import mapValues from './utils/mapValues'
 
 const withStateHandlers = (initialState, stateUpdaters) => BaseComponent => {
@@ -27,14 +26,6 @@ const withStateHandlers = (initialState, stateUpdaters) => BaseComponent => {
       }
     )
 
-    shouldComponentUpdate(nextProps, nextState) {
-      const propsChanged = nextProps !== this.props
-      // the idea is to skip render if stateUpdater handler return undefined
-      // this allows to create no state update handlers with access to state and props
-      const stateChanged = !shallowEqual(nextState, this.state)
-      return propsChanged || stateChanged
-    }
-
     render() {
       return factory({
         ...this.props,