Convert RelayReader-test.js to use new compiler

Summary:
We're working on deprecating JS compiler.
One of the steps, is to remove it from our unit-tests.

This is the test from #3199

Steps:
1) Remove `generateAndCompile`
2) Wrap graphql documents with `graphql` tag + add unique prefix
3) Run new compiler: `scripts/compile-tests.sh`

Reviewed By: kassens

Differential Revision: D25890200

fbshipit-source-id: 8432593ab5ab2ea3675a3331ad5c3d52fce9ab6f

Author: alunyov