Method Field Invoker reflection performance optimization, Supports JD…

[qmdx]

Added reflection performance optimization for MethodInvoker.java, modified to use MethodHandles instead of Reflection.

1，Invocation.java list targetClasses change set. Gain higher performance

2，Compatible with JDK 8 reflection

Reflection vs MethodHandles API in Java: Performance, Use Cases, and Best Practices
https://prgrmmng.com/reflection-vs-methodhandles-api-java

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Method	time
directCall	~1 ns
methodHandleExact	~2–4 ns
methodHandleInvoke	~4–8 ns
reflectionCall	~15–30 ns
Resolve reflective metadata at startup, convert it to MethodHandles, and eliminate reflection from the hot path.

Approach	Relative Cost	Notes
Direct field access	1×	Baseline
MethodHandle getter	1.2×	JIT inlineable
Method call via reflection	6–10×	Access checks + JNI
Field.get()	8–15×	Worst case

[harawata]

Hello @qmdx ,

Thank you for the PR.
I haven't looked into the details, but MyBatis 3.6.x will require Java 17, so please remove the Java 8 compatibility part of the change.