Update Python and JS test coverage collection to exclude tests

.coveragerc

@@ -6,6 +6,7 @@ source = wagtail
 
 omit =
     */migrations/*
+    */tests/*
     docs/conf.py
 
 

package.json

@@ -44,6 +44,10 @@
       "/node_modules/",
       "/build/"
     ],
+    "coveragePathIgnorePatterns": [
+      "/node_modules/",
+      "/tests/"
+    ],
     "setupFiles": [
       "./client/tests/adapter.js",
       "./client/tests/stubs.js",