Update Ant support following changes the executable jar layout

Closes gh-4897

spring-boot-tools/spring-boot-antlib/src/main/resources/org/springframework/boot/ant/antlib.xml

@@ -60,11 +60,14 @@
 
 			<echo>Embedding spring-boot-loader v${spring-boot.version}...</echo>
 			<jar destfile="@{destfile}" compress="false">
-				<fileset dir="@{classes}" />
+				<mappedresources>
+					<fileset dir="@{classes}"/>
+					<globmapper from="*" to="BOOT-INF/classes/*" />
+				</mappedresources>
 				<resources />
 				<mappedresources>
 					<lib />
-					<globmapper from="*" to="lib/*" />
+					<globmapper from="*" to="BOOT-INF/lib/*" />
 				</mappedresources>
 				<zipfileset src="${destdir}/dependency/spring-boot-loader.jar" />
 				<manifest>