Use Matcher from pre-compiled Pattern rather than String for replaceAll

Closes gh-14483

spring-boot-tests/spring-boot-integration-tests/spring-boot-devtools-tests/src/test/java/org/springframework/boot/devtools/tests/JvmLauncher.java

@@ -21,6 +21,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.regex.Pattern;
 
 import org.junit.rules.TestRule;
 import org.junit.runner.Description;
@@ -36,12 +37,14 @@ import org.springframework.util.StringUtils;
  */
 class JvmLauncher implements TestRule {
 
+	private static final Pattern NON_ALPHABET_PATTERN = Pattern.compile("[^A-Za-z]+");
+
 	private File outputDirectory;
 
 	@Override
 	public Statement apply(Statement base, Description description) {
-		this.outputDirectory = new File("target/output/"
-				+ description.getMethodName().replaceAll("[^A-Za-z]+", ""));
+		this.outputDirectory = new File("target/output/" + NON_ALPHABET_PATTERN
+				.matcher(description.getMethodName()).replaceAll(""));
 		this.outputDirectory.mkdirs();
 		return base;
 	}