Avoid ambiguous call with BeanInstanceSupplier#withGenerator

Previously, BeanInstanceSupplier had three variants of the
`withGenerator` callback, one with a bi function, one with a function,
and with a supplier. This could lead to compilation failure when the
target type has a method with the same name and a number of arguments
that match another variant.

It turns out the supplier-based variant is only used a shortcut. This
commit deprecates it and update ghe code generation to use the function
instead.

Closes gh-29278

spring-beans/src/main/java/org/springframework/beans/factory/aot/BeanInstanceSupplier.java

@@ -172,7 +172,9 @@ public final class BeanInstanceSupplier<T> extends AutowiredElementResolver impl
 	 * {@code generator} supplier to instantiate the underlying bean.
 	 * @param generator a {@link ThrowingSupplier} to instantiate the underlying bean
 	 * @return a new {@link BeanInstanceSupplier} instance with the specified generator
+	 * @deprecated in favor of {@link #withGenerator(ThrowingFunction)}
 	 */
+	@Deprecated(since = "6.0.11", forRemoval = true)
 	public BeanInstanceSupplier<T> withGenerator(ThrowingSupplier<T> generator) {
 		Assert.notNull(generator, "'generator' must not be null");
 		return new BeanInstanceSupplier<>(this.lookup,

spring-beans/src/main/java/org/springframework/beans/factory/aot/InstanceSupplierCodeGenerator.java

@@ -220,7 +220,8 @@ class InstanceSupplierCodeGenerator {
 			CodeBlock.Builder code = CodeBlock.builder();
 			code.add("$T.<$T>forFactoryMethod($T.class, $S)", BeanInstanceSupplier.class,
 					suppliedType, declaringClass, factoryMethod.getName());
-			code.add(".withGenerator($T::$L)", declaringClass, factoryMethod.getName());
+			code.add(".withGenerator(($L) -> $T.$L())", REGISTERED_BEAN_PARAMETER_NAME,
+					declaringClass, factoryMethod.getName());
 			return code.build();
 		}