Ensure associations doesn't table name collide with aliased joins

Currently alias tracker only refer a table name, doesn't respect an
alias name. Should use `join.left.name` rather than
`join.left.table_name`.

activerecord/lib/active_record/associations/alias_tracker.rb

@@ -31,7 +31,7 @@ module ActiveRecord
               /JOIN(?:\s+\w+)?\s+(?:\S+\s+)?(?:#{quoted_name}|#{name})\sON/i
             ).size
           elsif join.respond_to? :left
-            join.left.table_name == name ? 1 : 0
+            join.left.name == name ? 1 : 0
           elsif join.is_a?(Hash)
             join[name]
           else

activerecord/test/cases/associations/inner_join_association_test.rb

@@ -37,6 +37,14 @@ class InnerJoinAssociationTest < ActiveRecord::TestCase
     assert_match(/agents_people_2/i, sql)
   end
 
+  def test_construct_finder_sql_does_not_table_name_collide_with_aliased_joins
+    people = Person.arel_table
+    agents = people.alias("agents_people")
+    constraint = agents[:primary_contact_id].eq(people[:id])
+    sql = Person.joins(:agents).joins(agents.create_join(agents, agents.create_on(constraint))).to_sql
+    assert_match(/agents_people_2/i, sql)
+  end
+
   def test_construct_finder_sql_ignores_empty_joins_hash
     sql = Author.joins({}).to_sql
     assert_no_match(/JOIN/i, sql)