Are there any rowhammer resistance phones? It's taken 31 years but someone finally get around to implementing rowhammer for the arm instruction set.

So are there any ECC or MEU RAM chips available for phones or currently in use in any phones?
The list from the
Drammer app mentioned in your first link, shows some devices are not vulnerable, E.g, HTC Desire 510.( Row hammer wiki suggests that ECC overcomes TRR mentioned below the table)

Quoting from Source

We encourage everybody to try our Drammer test app and help figuring out how widespread mobile Rowhammer is. We expect, for example, that devices equipped with LPDDR4 are less vulnerable. This is because the LPDDR4 standard includes optional hardware support for the so-called target row refresh mitigation.
I have a phone with LPDDR4 memory. Am I safe against Drammer attacks?
Again, we don’t know. Chances are that your DRAM comes with the Target Row Refresh (TRR) mitigation, which makes it harder – but still not impossible, in theory – to induce bit flips. Moreover, TRR for LPDDR4 is optional, so your DRAM manufacturer may have decided to drop this technique and leave you vulnerable.

I doubt if you get that specific confirmation of implementation as you can see from How to know whether a RAM module is vulnerable to rowhammer before buying? a question on Security SE
From another question on Security SE, answers imply ECC is not necessarily a protection against the rowhammer vulnerability

Using ECC, whilst not a guarantee of security, might lower the probability of successful exploitation.

Edit: Based on the paper submitted on 26 Oct 16 by the authors in the annual CCS 2016 , which is quite beyond my understanding, my conclusions are :

There are many countermeasures and ECC is one of them ( clearly my understanding that ECC was the sole reason is wrong as also pointed out by OP in comments

Following devices were shown to be not vulnerable in the tests and as mentioned in the conclusion of paper x86 devices are not