Remove unused `blob_or_text_column?` method

activerecord/lib/active_record/connection_adapters/mysql/column.rb

@@ -4,10 +4,6 @@ module MySQL
       class Column < ConnectionAdapters::Column # :nodoc:
         delegate :extra, to: :sql_type_metadata, allow_nil: true
 
-        def blob_or_text_column?
-          /\A(?:tiny|medium|long)?blob\b/ === sql_type || type == :text
-        end
-
         def unsigned?
           /\bunsigned\z/ === sql_type
         end

activerecord/test/cases/adapters/mysql2/enum_test.rb

@@ -9,11 +9,6 @@ def test_enum_limit
     assert_equal 8, column.limit
   end
 
-  def test_should_not_be_blob_or_text_column
-    column = EnumTest.columns_hash["enum_column"]
-    assert_not column.blob_or_text_column?
-  end
-
   def test_should_not_be_unsigned
     column = EnumTest.columns_hash["enum_column"]
     assert_not column.unsigned?