Fixed jdk8 Map computeIfAbsent performance bug

[caojiajun]

Fixed jdk8 Map computeIfAbsent performance bug
see https://bugs.openjdk.org/browse/JDK-8161372

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• You submit test cases (unit or integration tests) that back your changes.
• Your local test passed ./mvnw clean install -Dmaven.javadoc.skip=true.

[caojiajun]

add this utils method in MapUtils, and replace the computeIfAbsent direct invoke in project

    /**
     * jdk8 performance bug, see: https://bugs.openjdk.java.net/browse/JDK-8161372
     *
     * @param map source map
     * @param key key
     * @param mappingFunction mappingFunction
     * @param <K> k
     * @param <V> v
     * @return v
     */
    public static <K, V> V computeIfAbsent(Map<K, V> map, K key, Function<? super K, ? extends V> mappingFunction) {
        V v = map.get(key);
        if (v != null) return v;
        return map.computeIfAbsent(key, mappingFunction);
    }

[caojiajun]

@midnight2104 pls help me review this pr