Increase suggested gas percentile to 65 (#5359)

* Increase suggested gas percentile to 65

I keep submitting transactions then waiting a long time. Apparently 50th percentile isn't enough.

* Update test for getGasPrice

app/scripts/metamask-controller.js

@@ -1363,7 +1363,7 @@ module.exports = class MetamaskController extends EventEmitter {
     })
     .map(number => number.div(GWEI_BN).toNumber())
 
-    const percentileNum = percentile(50, lowestPrices)
+    const percentileNum = percentile(65, lowestPrices)
     const percentileNumBn = new BN(percentileNum)
     return '0x' + percentileNumBn.mul(GWEI_BN).toString(16)
   }

test/unit/app/controllers/metamask-controller-test.js

@@ -116,7 +116,7 @@ describe('MetaMaskController', function () {
       }
 
       const gasPrice = metamaskController.getGasPrice()
-      assert.equal(gasPrice, '0x3b9aca00', 'accurately estimates 50th percentile accepted gas price')
+      assert.equal(gasPrice, '0x174876e800', 'accurately estimates 65th percentile accepted gas price')
 
       metamaskController.recentBlocksController = realRecentBlocksController
     })