Avoid the need to specify Supplier in Kotlin bean registration API

Based on an idea from Mario Arias, we can avoid requiring specifying
explicitly Supplier lambda type in Kotlin API by declaring the supplier
parameter as "crossinline supplier: () -> T" instead of
"supplier: Supplier<T>".

Issue: SPR-15118

spring-context/src/main/kotlin/org/springframework/context/support/GenericApplicationContextExtension.kt

@@ -33,16 +33,16 @@ object GenericApplicationContextExtension {
 	/**
 	 * @see GenericApplicationContext.registerBean(Class<T>, Supplier<T>, BeanDefinitionCustomizer...)
 	 */
-	inline fun <reified T : Any> GenericApplicationContext.registerBean(supplier: Supplier<T>,
-			vararg customizers: BeanDefinitionCustomizer) {
-					registerBean(T::class.java, supplier, *customizers)
+	inline fun <reified T : Any> GenericApplicationContext.registerBean(
+			crossinline supplier: () -> T, vararg customizers: BeanDefinitionCustomizer) {
+					registerBean(T::class.java, Supplier { supplier.invoke() }, *customizers)
 	}
 
 	/**
 	 * @see GenericApplicationContext.registerBean(String, Class<T>, Supplier<T>, BeanDefinitionCustomizer...)
 	 */
 	inline fun <reified T : Any> GenericApplicationContext.registerBean(name: String,
-			supplier: Supplier<T>, vararg customizers: BeanDefinitionCustomizer) {
-					registerBean(name, T::class.java, supplier, *customizers)
+			crossinline supplier: () -> T, vararg customizers: BeanDefinitionCustomizer) {
+					registerBean(name, T::class.java, Supplier { supplier.invoke() }, *customizers)
 	}
 }

spring-context/src/test/kotlin/org/springframework/context/support/GenericApplicationContextExtensionTests.kt

@@ -4,7 +4,6 @@ import org.junit.Assert.assertNotNull
 import org.junit.Test
 import org.springframework.context.support.GenericApplicationContextExtension.registerBean
 import org.springframework.beans.factory.BeanFactoryExtension.getBean
-import java.util.function.Supplier
 
 class GenericApplicationContextExtensionTests {
 
@@ -27,7 +26,7 @@ class GenericApplicationContextExtensionTests {
 	@Test
 	fun registerBeanWithSupplier() {
 		val context = GenericApplicationContext()
-		context.registerBean(Supplier { BeanA() })
+		context.registerBean({ BeanA() })
 		context.refresh()
 		assertNotNull(context.getBean(BeanA::class))
 	}
@@ -35,7 +34,7 @@ class GenericApplicationContextExtensionTests {
 	@Test
 	fun registerBeanWithNameAndSupplier() {
 		val context = GenericApplicationContext()
-		context.registerBean("a",  Supplier { BeanA() })
+		context.registerBean("a", { BeanA() })
 		context.refresh()
 		assertNotNull(context.getBean("a"))
 	}