Use TRUE and FALSE for booleans in SQLite

Previously, queries generated with boolean comparisons for MySQL and
Postgres used `TRUE` and `FALSE` (these are actual booleans in Postgres
and aliases for `1`/`0` in MySQL) but used `1` and `0` for SQLite. This
makes it more difficult to write database-agnostic query assertions,
since the values are different.

SQLite 3.23.0 added support for `TRUE` and `FALSE` as aliases for
`1`/`0` (similar to MySQL). A [previous commit][1] bumped the minimum
required SQLite version in Active Record to 3.23.0, and this commit
updates the boolean query generation for SQLite to use `TRUE` and
`FALSE`.

[1]: 809abd3

Author: skipkayhil

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Use `TRUE` and `FALSE` for SQLite queries with boolean columns.
+
+    *Hartley McGuire*
+
 *   Bump minimum supported SQLite to 3.23.0.
 
     *Hartley McGuire*

activerecord/lib/arel/visitors/sqlite.rb

@@ -68,14 +68,6 @@ def visit_Arel_Nodes_SelectStatement(o, collector)
           super
         end
 
-        def visit_Arel_Nodes_True(o, collector)
-          collector << "1"
-        end
-
-        def visit_Arel_Nodes_False(o, collector)
-          collector << "0"
-        end
-
         def visit_Arel_Nodes_IsNotDistinctFrom(o, collector)
           collector = visit o.left, collector
           collector << " IS "

activerecord/test/cases/arel/visitors/sqlite_test.rb

@@ -25,13 +25,6 @@ def compile(node)
         assert_equal "", @visitor.accept(node, Collectors::SQLString.new).value
       end
 
-      it "does not support boolean" do
-        node = Nodes::True.new()
-        assert_equal "1", @visitor.accept(node, Collectors::SQLString.new).value
-        node = Nodes::False.new()
-        assert_equal "0", @visitor.accept(node, Collectors::SQLString.new).value
-      end
-
       describe "Nodes::IsNotDistinctFrom" do
         it "should construct a valid generic SQL statement" do
           test = Table.new(:users)[:name].is_not_distinct_from "Aaron Patterson"