[Bug]: Type reference building logic fails within lambda bodies

### Describe the bug

Something seems to go wrong with type reference parsing within method bodies when `extends` is involved. The following fails with the included stack trace:
```java
Launcher.parseClass("""
public class Test {
public static void test() {
final Supplier supplier = () -> {
final Supplier> supplier1 = () -> a -> a;
return supplier1;
};
}
}""");
```
However, each of the following succeed:
```java
Launcher.parseClass("""
public class Test {
public static void test() {
final Supplier supplier = () -> {
final Supplier> supplier1 = () -> a -> a;
return supplier1;
};
}
}""");
```
```java
Launcher.parseClass("""
public class Test {
public static void test() {
final Supplier supplier = () -> {
final Supplier> supplier1 = () -> () -> new Object();
return supplier1;
};
}
}""");
```
```java
Launcher.parseClass("""
public class Test {
public static void test() {
final Supplier> supplier = () -> a -> a;
}
}""");
```
In other words, it only seems to apply with the combination of the local definition being within a lambda, the `extends` being present, and the nested type being parameterized by more than one type (so that it is split on the comma when the outer one is being processed)

### Actual output

```Java
Caused by: spoon.JLSViolation: Not allowed javaletter or keyword in identifier found. See JLS for correct identifier. Identifier: Function