Simplify to a single instance variable for #same_working_directory_for_load_path?

(cherry picked from commit c1d8c1a)

Author: eregon

src/main/ruby/truffleruby/core/truffle/feature_loader.rb

@@ -21,7 +21,7 @@ module FeatureLoader
     @expanded_load_path = []
     # A snapshot of $LOAD_PATH, to check if the @expanded_load_path cache is up to date.
     @load_path_copy = []
-    @relative_path_in_load_path = false
+    # nil if there is no relative path in $LOAD_PATH, a copy of the cwd to check if the cwd changed otherwise.
     @working_directory_copy = nil
 
     def self.clear_cache
@@ -284,10 +284,9 @@ def self.get_expanded_load_path
       unless Primitive.array_storage_equal?(@load_path_copy, $LOAD_PATH) && same_working_directory_for_load_path?
         @expanded_load_path = $LOAD_PATH.map do |path|
           path = Truffle::Type.coerce_to_path(path)
-          unless @relative_path_in_load_path
+          unless @working_directory_copy
             unless File.absolute_path?(path)
               @working_directory_copy = Primitive.working_directory
-              @relative_path_in_load_path = true
             end
           end
           Primitive.canonicalize_path(path)
@@ -298,8 +297,8 @@ def self.get_expanded_load_path
     end
 
     def self.same_working_directory_for_load_path?
-      if @relative_path_in_load_path
-        if Primitive.working_directory == @working_directory_copy
+      if working_directory_copy = @working_directory_copy
+        if Primitive.working_directory == working_directory_copy
           true
         else
           @working_directory_copy = Primitive.working_directory