Fix tests for apollo-graphql by adding jest config.

I observed that the tests weren't running for the `apollo-graphql` package
when reviewing the work in #1018.

Upon investigating further (via `jest --debug`), it seems that the Jest
configuration was missing the appropriate configuration for it to pickup the
extensions of `ts` and `tsx` within the `apollo-graphql` repository.

It was only then that I realized that this repository still has `jest`
configuration defined in each of its `package.json` files, rather than a
monorepo-root `jest.config.base.json` file.  That's fine, but it caught me
off guard.

I do think that we should try to DRY-up this repetition and align this
across teams and repositories as soon as possible because it's difficult to
start building per-package exceptions which will quickly become hard to
manage.  For now, this will get tests working for `apollo-graphql` within
the scope of the PR that brings it into the `apollo-tooling` repository,
which seems necessary to tick the box for shipping that PR.

packages/apollo-graphql/package.json

@@ -15,5 +15,35 @@
   },
   "peerDependencies": {
     "graphql": "^14.0.2"
+  },
+  "jest": {
+    "preset": "ts-jest",
+    "transformIgnorePatterns": [
+      "/node_modules/",
+      "/apollo-env/"
+    ],
+    "testEnvironment": "node",
+    "testMatch": [
+      "**/__tests__/*.(js|ts)"
+    ],
+    "setupFiles": [
+      "<rootDir>/../apollo-env/lib/index.js"
+    ],
+    "testPathIgnorePatterns": [
+      "<rootDir>/node_modules/",
+      "<rootDir>/lib/",
+      "<rootDir>/test/fixtures/",
+      "<rootDir>/test/test-utils"
+    ],
+    "moduleFileExtensions": [
+      "ts",
+      "js"
+    ],
+    "globals": {
+      "ts-jest": {
+        "tsConfig": "<rootDir>/tsconfig.test.json",
+        "diagnostics": false
+      }
+    }
   }
 }