Fix incorrect UNIQUE constraint failure behavior in UPDATE

UPDATE should skip over the UNIQUE constraint failure if the existing
row it found during the check has the same rowid as the row we are
currently updating

core/translate/emitter.rs

@@ -1056,8 +1056,10 @@ fn emit_update_insns(
             dest: idx_rowid_reg,
         });
 
+        // Skip over the UNIQUE constraint failure if the existing row is the one that we are currently changing
+        let original_rowid_reg = beg;
         program.emit_insn(Insn::Eq {
-            lhs: rowid_reg,
+            lhs: original_rowid_reg,
             rhs: idx_rowid_reg,
             target_pc: constraint_check,
             flags: CmpInsFlags::default(), // TODO: not sure what type of comparison flag is needed