Changed internal representation of booleans

Instead of an explicit value (field 'b'), true and false use different
tag variants. This avoids reading an extra field and results in more
direct code. (Most code that uses booleans needs to distinguish between
true and false anyway.)

testes/code.lua

@@ -144,10 +144,10 @@ check(function (a,b,c,d) return a..b..c..d end,
   'MOVE', 'MOVE', 'MOVE', 'MOVE', 'CONCAT', 'RETURN1')
 
 -- not
-check(function () return not not nil end, 'LOADBOOL', 'RETURN1')
-check(function () return not not kFalse end, 'LOADBOOL', 'RETURN1')
-check(function () return not not true end, 'LOADBOOL', 'RETURN1')
-check(function () return not not k3 end, 'LOADBOOL', 'RETURN1')
+check(function () return not not nil end, 'LOADFALSE', 'RETURN1')
+check(function () return not not kFalse end, 'LOADFALSE', 'RETURN1')
+check(function () return not not true end, 'LOADTRUE', 'RETURN1')
+check(function () return not not k3 end, 'LOADTRUE', 'RETURN1')
 
 -- direct access to locals
 check(function ()
@@ -194,7 +194,7 @@ check(function ()
   local a,b
   a[kTrue] = false
 end,
-  'LOADNIL', 'LOADBOOL', 'SETTABLE', 'RETURN0')
+  'LOADNIL', 'LOADTRUE', 'SETTABLE', 'RETURN0')
 
 
 -- equalities