Enhance the OP_IdxInsert opcode to optionally accept unpacked key material.

FossilOrigin-Name: 89d958abbac45f2ca5954080cd9e74ec9a07ebb2
diff --git a/src/insert.c b/src/insert.c
index 6ea3810..14186b2 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -2180,8 +2180,8 @@
     if( !HasRowid(pSrc) && pDestIdx->idxType==2 ){
       idxInsFlags |= OPFLAG_NCHANGE;
     }
-    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
-    sqlite3VdbeChangeP5(v, idxInsFlags);
+    sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
+    sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
     sqlite3VdbeJumpHere(v, addr1);
     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);