Migrate remaining SWT tests to use text blocks

Author: ptziegler

org.eclipse.wb.tests/src/org/eclipse/wb/tests/designer/swt/ManagerUtilsTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -144,12 +144,11 @@ public void test_ensure_ResourceManager() throws Exception {
 	}
 
 	private void parseShell() throws Exception {
-		shell =
-				parseComposite(
-						"// filler filler filler",
-						"public class Test extends Shell {",
-						"  public Test() {",
-						"  }",
-						"}");
+		shell = parseComposite("""
+				// filler filler filler
+				public class Test extends Shell {
+					public Test() {
+					}
+				}""");
 	}
 }