remove timestamp for kovan

libs/remix-lib/src/execution/txRunnerWeb3.ts

@@ -72,15 +72,21 @@ export class TxRunnerWeb3 {
     const tx = { from: from, to: to, data: data, value: value }
 
     if (useCall) {
-      const tag = Date.now() // for e2e reference
       tx['gas'] = gasLimit
-      // tx['timestamp'] = timestamp
+      tx['timestamp'] = timestamp
+      return this._api.detectNetwork((err, network) => {
+        if (err) {
+          console.log(err)
+          return
+        } else if (network && network.name === 'Kovan') delete tx['timestamp']
+
         return this.getWeb3().eth.call(tx, function (error, result: any) {
           if (error) return callback(error)
           callback(null, {
             result: result
           })
         })
+      })
     }
     this.getWeb3().eth.estimateGas(tx, (err, gasEstimation) => {
       if (err && err.message.indexOf('Invalid JSON RPC response') !== -1) {