Add junit-platform-launcher dependency

Update `build.gradle` files to ensure that `junit-platform-launcher` is
a `testRuntimeOnly` dependency. This ensures that tests can be run from
Eclipse.

Closes gh-25074

spring-boot-project/spring-boot-tools/spring-boot-loader/build.gradle

@@ -18,6 +18,7 @@ dependencies {
 
 	testRuntimeOnly("ch.qos.logback:logback-classic")
 	testRuntimeOnly("org.bouncycastle:bcprov-jdk16:1.46")
+	testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 	testRuntimeOnly("org.slf4j:jcl-over-slf4j")
 	testRuntimeOnly("org.springframework:spring-webmvc")
-}
+}