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/test/java/org/springframework/beans/factory/aot/BeanInstanceSupplierTests.java

@@ -186,6 +186,8 @@ class BeanInstanceSupplierTests {
 	}
 
 	@Test
+	@Deprecated
+	@SuppressWarnings("removal")
 	void withGeneratorWhenSupplierIsNullThrowsException() {
 		BeanInstanceSupplier<Object> resolver = BeanInstanceSupplier
 				.forConstructor();
@@ -245,6 +247,8 @@ class BeanInstanceSupplierTests {
 	}
 
 	@Test
+	@Deprecated
+	@SuppressWarnings("removal")
 	void getWithGeneratorCallsSupplier() throws Exception {
 		BeanRegistrar registrar = new BeanRegistrar(SingleArgConstructor.class);
 		this.beanFactory.registerSingleton("one", "1");

spring-beans/src/test/java/org/springframework/beans/factory/aot/InstanceSupplierCodeGeneratorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -223,7 +223,7 @@ class InstanceSupplierCodeGeneratorTests {
 			assertThat(bean).isInstanceOf(Integer.class);
 			assertThat(bean).isEqualTo(42);
 			assertThat(compiled.getSourceFile())
-					.contains("SimpleConfiguration::integerBean");
+					.contains("(registeredBean) -> SimpleConfiguration.integerBean()");
 		});
 		assertThat(getReflectionHints().getTypeHint(SimpleConfiguration.class))
 				.satisfies(hasMethodWithMode(ExecutableMode.INTROSPECT));