Remove JUnit 5 dependencies

Issue gh-674

samples/custom-consent-authorizationserver/samples-custom-consent-authorizationserver.gradle

@@ -19,13 +19,7 @@ dependencies {
 	implementation project(":spring-security-oauth2-authorization-server")
 
 	testImplementation "org.springframework.boot:spring-boot-starter-test"
-	testImplementation "org.junit.jupiter:junit-jupiter"
-	testImplementation "junit:junit"
-	testImplementation "org.junit.vintage:junit-vintage-engine"
 	testImplementation "org.springframework.security:spring-security-test"
+	testImplementation "junit:junit"
 	testImplementation "net.sourceforge.htmlunit:htmlunit"
 }
-
-tasks.named("test") {
-	useJUnitPlatform()
-}

samples/default-authorizationserver/samples-default-authorizationserver.gradle

@@ -20,13 +20,7 @@ dependencies {
 	runtimeOnly "com.h2database:h2"
 
 	testImplementation "org.springframework.boot:spring-boot-starter-test"
-	testImplementation "org.junit.jupiter:junit-jupiter"
-	testImplementation "junit:junit"
-	testImplementation "org.junit.vintage:junit-vintage-engine"
 	testImplementation "org.springframework.security:spring-security-test"
+	testImplementation "junit:junit"
 	testImplementation "net.sourceforge.htmlunit:htmlunit"
 }
-
-tasks.named("test") {
-	useJUnitPlatform()
-}

samples/federated-identity-authorizationserver/samples-federated-identity-authorizationserver.gradle

@@ -24,7 +24,3 @@ dependencies {
 	implementation project(":spring-security-oauth2-authorization-server")
 	runtimeOnly "com.h2database:h2"
 }
-
-tasks.named("test") {
-	useJUnitPlatform()
-}

samples/messages-client/samples-messages-client.gradle

@@ -24,7 +24,3 @@ dependencies {
 	implementation "org.webjars:bootstrap:3.4.1"
 	implementation "org.webjars:jquery:3.4.1"
 }
-
-tasks.named("test") {
-	useJUnitPlatform()
-}

samples/messages-resource/samples-messages-resource.gradle

@@ -17,7 +17,3 @@ dependencies {
 	implementation "org.springframework.boot:spring-boot-starter-security"
 	implementation "org.springframework.boot:spring-boot-starter-oauth2-resource-server"
 }
-
-tasks.named("test") {
-	useJUnitPlatform()
-}