accounts/keystore: fix double import race (#20915)

* accounts/keystore: fix race in Import/ImportECDSA

* accounts/keystore: added import/export tests

* cmd/geth: improved TestAccountImport test

* accounts/keystore: added import/export tests

* accounts/keystore: fixed naming

* accounts/keystore: fixed typo

* accounts/keystore: use mutex instead of rwmutex

* accounts: use errors instead of fmt

cmd/geth/accountcmd_test.go

@@ -89,18 +89,23 @@ Path of the secret key file: .*UTC--.+--[0-9a-f]{40}
 }
 
 func TestAccountImport(t *testing.T) {
-	tests := []struct{ key, output string }{
+	tests := []struct{ name, key, output string }{
 		{
+			name:   "correct account",
 			key:    "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
 			output: "Address: {fcad0b19bb29d4674531d6f115237e16afce377c}\n",
 		},
 		{
+			name:   "invalid character",
 			key:    "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef1",
 			output: "Fatal: Failed to load the private key: invalid character '1' at end of key file\n",
 		},
 	}
 	for _, test := range tests {
-		importAccountWithExpect(t, test.key, test.output)
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			importAccountWithExpect(t, test.key, test.output)
+		})
 	}
 }