Add "noImplicitThis" to all tsconfig.json (#13446)

* Add "noImplicitThis" to all tsconfig.json

* Use `"noImplicitThis": false` on packages with broken tests.

node-fetch/tsconfig.json

@@ -3,6 +3,7 @@
         "module": "commonjs",
         "target": "es6",
         "noImplicitAny": true,
+        "noImplicitThis": true,
         "strictNullChecks": false,
         "baseUrl": "../",
         "typeRoots": [
@@ -11,10 +12,13 @@
         "types": [],
         "noEmit": true,
         "forceConsistentCasingInFileNames": true,
-        "lib": ["es5", "es6"]
+        "lib": [
+            "es5",
+            "es6"
+        ]
     },
     "files": [
         "index.d.ts",
         "node-fetch-tests.ts"
     ]
-}
+}