[BUG] ExtensionMethod for generic types does not work with generic parameters in ecj

[Rawi01]

Describe the bug
Adding extension methods for generic types seems to be broken if there also is a generic parameter. I think I broke this while working a bunch of other bugs. I will try to fix this myself...

To Reproduce

import java.util.Arrays;
import java.util.List;

import lombok.experimental.ExtensionMethod;

@ExtensionMethod(ExtensionMethodGeneric.Extensions.class)
class ExtensionMethodGeneric {
	public void test() {
		List<String> stringList;
		List<Number> numberList;
		
		stringList.test(numberList);
	}
	
	static class Extensions {
		public static <T> void test(List<String> obj, List<T> list) {
			
		}
	}
}

12 ERROR The parameterized method <String>test(List<String>, List<String>) of type ExtensionMethodGeneric.Extensions is not applicable for the arguments (List<String>, List<Number>)

Expected behavior
It compiles without any error as it does if you call the extension method by hand.

Version info:

• Lombok version: 1.18.16
• Platform: Eclipse 2020-09

Additional context
This is a simplified example, there might be more problems if you use more complex generic stuff.

[Rawi01]

I added some code to copy generic information which seems to break this example:
https://github.com/rzwitserloot/lombok/blob/e1f82ac4d132769cfc272dccfc916aeba7181718/src/eclipseAgent/lombok/eclipse/agent/PatchExtensionMethod.java#L307-L314
Removing this code snippet fixes the issue and all tests still pass, I guess that I should share the more complex cases somewhere next time 😄 , now I have to figure out why I added this stuff

[Rawi01]

Was about to send a PR to remove the block but finally figured out what I tried to solve:

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import lombok.experimental.ExtensionMethod;

@ExtensionMethod(ExtensionMethodGeneric.Extensions.class)
class ExtensionMethodGeneric {
	public void test() {
		Stream.of("a", "b", "c").map(String::toUpperCase).toList();
	}

	static class Extensions {
		public static <T> List<T> toList(Stream<T> stream) {
			return (List<T>) stream.collect(Collectors.toList());
		}
	}
}