refactor: do not infer project root from script location (#1265)

* fix(Api): do not infer project root from script location

* fix(builders): do not infer project root from script location

* fix(target): do not infer project root from script location

* test(e2e): cleanup and extend E2E tests

- Renames the file with the only existing E2E test
- Makes existing test use the API instance returned by
  `Api.createPlatform`
- Adds another test that ensures we can still require the API from
  `platformProjectPath/cordova/Api.js`

* fix(check_reqs): do not infer project root from script location

spec/unit/builders/ProjectBuilder.spec.js

@@ -43,10 +43,8 @@ describe('ProjectBuilder', () => {
             expect(builder.root).toBe(rootDir);
         });
 
-        it('should set the project directory to three folders up', () => {
-            ProjectBuilder.__set__('__dirname', 'projecttest/platforms/android/app');
-            builder = new ProjectBuilder();
-            expect(builder.root).toMatch(/projecttest$/);
+        it('should throw if project directory is missing', () => {
+            expect(() => new ProjectBuilder()).toThrowError(TypeError);
         });
     });
 
@@ -224,7 +222,7 @@ describe('ProjectBuilder', () => {
             return builder.build({}).then(
                 () => fail('Unexpectedly resolved'),
                 error => {
-                    expect(checkReqsSpy.check_android_target).toHaveBeenCalled();
+                    expect(checkReqsSpy.check_android_target).toHaveBeenCalledWith(rootDir);
                     expect(error).toBe(testError);
                 }
             );