Remove unused ByteArrayStartsWith matcher

Closes gh-15386

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/ByteArrayStartsWith.java

@@ -1,53 +0,0 @@
-/*
- * Copyright 2012-2017 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.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.boot.loader;
-
-import org.hamcrest.Description;
-import org.hamcrest.TypeSafeMatcher;
-
-/**
- * Hamcrest matcher to tests that a byte array starts with specific bytes.
- *
- * @author Phillip Webb
- */
-public class ByteArrayStartsWith extends TypeSafeMatcher<byte[]> {
-
-	private final byte[] bytes;
-
-	public ByteArrayStartsWith(byte[] bytes) {
-		this.bytes = bytes;
-	}
-
-	@Override
-	public void describeTo(Description description) {
-		description.appendText("a byte array starting with ").appendValue(this.bytes);
-	}
-
-	@Override
-	protected boolean matchesSafely(byte[] item) {
-		if (item.length < this.bytes.length) {
-			return false;
-		}
-		for (int i = 0; i < this.bytes.length; i++) {
-			if (item[i] != this.bytes[i]) {
-				return false;
-			}
-		}
-		return true;
-	}
-
-}