[6.7] [junit] use default rootDirectory for project (#32256) (#32347)

Backports the following commits to 6.7:
 - [junit] use default rootDirectory for project  (#32256)

src/functional_test_runner/lib/config/schema.js

@@ -115,7 +115,6 @@ export const schema = Joi.object().keys({
   junit: Joi.object().keys({
     enabled: Joi.boolean().default(!!process.env.CI),
     reportName: Joi.string(),
-    rootDirectory: Joi.string(),
   }).default(),
 
   mochaReporter: Joi.object().keys({

src/functional_test_runner/lib/mocha/reporter/reporter.js

@@ -54,7 +54,6 @@ export function MochaReporterProvider({ getService }) {
       if (config.get('junit.enabled') && config.get('junit.reportName')) {
         setupJUnitReportGeneration(runner, {
           reportName: config.get('junit.reportName'),
-          rootDirectory: config.get('junit.rootDirectory')
         });
       }
     }

x-pack/dev-tools/jest/create_jest_config.js

@@ -49,7 +49,6 @@ export function createJestConfig({
       "default",
       [`${kibanaDirectory}/src/dev/jest/junit_reporter.js`, {
         reportName: 'X-Pack Jest Tests',
-        rootDirectory: xPackKibanaDirectory,
       }]
     ],
   };

x-pack/tasks/test.js

@@ -14,7 +14,6 @@ const MOCHA_OPTIONS = {
   ui: 'bdd',
   reporter: createAutoJUnitReporter({
     reportName: 'X-Pack Mocha Tests',
-    rootDirectory: __dirname,
   }),
 };
 

x-pack/test/functional/config.js

@@ -227,7 +227,6 @@ export default async function ({ readConfigFile }) {
 
     junit: {
       reportName: 'X-Pack Functional Tests',
-      rootDirectory: resolve(__dirname, '../../'),
     },
   };