Add assert() statements to refute

[forum:/forumpost/9f4e7f58fbb66ddd|forum post 9f4e7f58fbb66ddd].

FossilOrigin-Name: 83a83475c5064ea62016a03e9173ecd2a1fec7f6296f1ee99896fa0a38b4196a

src/window.c

@@ -1066,6 +1066,9 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
        ("New window-function subquery in FROM clause of (%u/%p)\n",
        p->selId, p));
     p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+    assert( pSub!=0 || p->pSrc==0 ); /* Due to db->mallocFailed test inside
+                                     ** of sqlite3DbMallocRawNN() called from
+                                     ** sqlite3SrcListAppend() */
     if( p->pSrc ){
       Table *pTab2;
       p->pSrc->a[0].pSelect = pSub;