core/state, light, les: make signature of ContractCode hash-independent (#27209)

* core/state, light, les: make signature of ContractCode hash-independent

* push current state for feedback

* les: fix unit test

* core, les, light: fix les unittests

* core/state, trie, les, light: fix state iterator

* core, les: address comments

* les: fix lint

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Co-authored-by: Gary Rong <garyrong0905@gmail.com>

trie/database_wrap.go

@@ -168,10 +168,15 @@ func (db *Database) Scheme() string {
 // It is meant to be called when closing the blockchain object, so that all
 // resources held can be released correctly.
 func (db *Database) Close() error {
+	db.WritePreimages()
+	return db.backend.Close()
+}
+
+// WritePreimages flushes all accumulated preimages to disk forcibly.
+func (db *Database) WritePreimages() {
 	if db.preimages != nil {
 		db.preimages.commit(true)
 	}
-	return db.backend.Close()
 }
 
 // saveCache saves clean state cache to given directory path