[rb] update managing root paths for testing

rb/lib/selenium/webdriver/common/selenium_manager.rb

diff --git a/rb/lib/selenium/webdriver/common/selenium_manager.rb b/rb/lib/selenium/webdriver/common/selenium_manager.rb
index 967a18c..be9f97a 100644
--- a/rb/lib/selenium/webdriver/common/selenium_manager.rb
+++ b/rb/lib/selenium/webdriver/common/selenium_manager.rb
@@ -17,6 +17,7 @@
 # specific language governing permissions and limitations
 # under the License.
 
+require 'bundler'
 require 'open3'
 
 module Selenium
@@ -28,12 +29,6 @@
     #
     class SeleniumManager
       class << self
-        attr_writer :bin_path
-
-        def bin_path
-          @bin_path ||= '../../../../../bin'
-        end
-
         # @param [Options] options browser options.
         # @return [String] the path to the correct driver.
         def driver_path(options)
@@ -76,17 +71,16 @@
         def binary
           @binary ||= begin
             location = ENV.fetch('SE_MANAGER_PATH', begin
-              directory = File.expand_path(bin_path, __FILE__)
               if Platform.windows?
-                "#{directory}/windows/selenium-manager.exe"
+                "#{Bundler.root}/bin/windows/selenium-manager.exe"
               elsif Platform.mac?
-                "#{directory}/macos/selenium-manager"
+                "#{Bundler.root}/bin/macos/selenium-manager"
               elsif Platform.linux?
-                "#{directory}/linux/selenium-manager"
+                "#{Bundler.root}/bin/linux/selenium-manager"
               elsif Platform.unix?
                 WebDriver.logger.warn('Selenium Manager binary may not be compatible with Unix; verify settings',
                                       id: %i[selenium_manager unix_binary])
-                "#{directory}/linux/selenium-manager"
+                "#{Bundler.root}/bin/linux/selenium-manager"
               end
             rescue Error::WebDriverError => e
               raise Error::WebDriverError, "Unable to obtain Selenium Manager binary for #{e.message}"

rb/spec/integration/selenium/webdriver/spec_support/test_environment.rb

diff --git a/rb/spec/integration/selenium/webdriver/spec_support/test_environment.rb b/rb/spec/integration/selenium/webdriver/spec_support/test_environment.rb
index 5ded602..9c8ad99 100644
--- a/rb/spec/integration/selenium/webdriver/spec_support/test_environment.rb
+++ b/rb/spec/integration/selenium/webdriver/spec_support/test_environment.rb
@@ -17,6 +17,8 @@
 # specific language governing permissions and limitations
 # under the License.
 
+require 'bundler'
+
 module Selenium
   module WebDriver
     module SpecSupport
@@ -27,10 +29,17 @@
           @create_driver_error = nil
           @create_driver_error_count = 0
 
-          $LOAD_PATH.insert(0, root.join('bazel-bin/rb/lib').to_s) if File.exist?(root.join('bazel-bin/rb/lib'))
-          WebDriver.logger.ignore(%i[logger_info])
-          SeleniumManager.bin_path = root.join('bazel-bin/rb/bin').to_s if File.exist?(root.join('bazel-bin/rb/bin'))
+          bazel_path = Bundler.root.join('bazel-bin/rb/').to_s
+          $LOAD_PATH.insert(0, "#{bazel_path}/lib").to_s
+          ENV['SE_MANAGER_PATH'] = if Platform.windows?
+                                     "#{bazel_path}/bin/windows/selenium-manager.exe"
+                                   elsif Platform.mac?
+                                     "#{bazel_path}/bin/macos/selenium-manager"
+                                   elsif Platform.linux?
+                                     "#{bazel_path}/bin/linux/selenium-manager"
+                                   end
 
+          WebDriver.logger.ignore(:logger_info)
           @driver = ENV.fetch('WD_SPEC_DRIVER', 'chrome').tr('-', '_').to_sym
           @driver_instance = nil
           @remote_server = nil
@@ -77,7 +86,7 @@
 
         def app_server
           @app_server ||= begin
-            app_server = RackServer.new(root.join('common/src/web').to_s, random_port)
+            app_server = RackServer.new(Bundler.root.join('common/src/web').to_s, random_port)
             app_server.start
 
             app_server
@@ -108,7 +117,7 @@
         def remote_server_jar
           jar = 'java/src/org/openqa/selenium/grid/selenium_server_deploy.jar'
           test_jar = Pathname.new(Dir.pwd).join(jar)
-          built_jar = root.join("bazel-bin/#{jar}")
+          built_jar = Bundler.root.join("bazel-bin/#{jar}")
           jar = if File.exist?(test_jar) && ENV['DOWNLOAD_SERVER'].nil?
                   test_jar
                 elsif File.exist?(built_jar) && ENV['DOWNLOAD_SERVER'].nil?
@@ -133,12 +142,6 @@
           app_server.where_is filename
         end
 
-        def root
-          # prefer #realpath over #expand_path to avoid problems with UNC
-          # see https://bugs.ruby-lang.org/issues/13515
-          @root ||= Pathname.new('../../../../../../../').realpath(__FILE__)
-        end
-
         def create_driver!(listener: nil, **opts, &block)
           check_for_previous_error