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.)

ldebug.c

@@ -306,7 +306,7 @@ static void collectvalidlines (lua_State *L, Closure *f) {
     Table *t = luaH_new(L);  /* new table to store active lines */
     sethvalue2s(L, L->top, t);  /* push it on stack */
     api_incr_top(L);
-    setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
+    setbtvalue(&v);  /* boolean 'true' to be the value of all indices */
     for (i = 0; i < p->sizelineinfo; i++) {  /* for all lines with code */
       currentline = nextline(p, currentline, i);
       luaH_setint(L, t, currentline, &v);  /* table[line] = true */