jsgen: bool genConv generates boolean values instead of numeric (#7016)

compiler/jsgen.nim

@@ -2051,10 +2051,10 @@ proc genConv(p: PProc, n: PNode, r: var TCompRes) =
     return
   case dest.kind:
   of tyBool:
-    r.res = "(($1)? 1:0)" % [r.res]
+    r.res = "(!!($1))" % [r.res]
     r.kind = resExpr
   of tyInt:
-    r.res = "($1|0)" % [r.res]
+    r.res = "(($1)|0)" % [r.res]
   else:
     # TODO: What types must we handle here?
     discard