Fix reliance on undefined behaviour for package naming semantics in multi-tiered test

Author: ascopes

java-compiler-testing/src/test/java/io/github/ascopes/jct/integration/compilation/MultiTieredCompilationIntegrationTest.java

@@ -91,6 +91,7 @@ void compileSourcesToClassesAndProvideThemInClassPathToSecondCompilationWithinJa
     ) {
       firstWorkspace
           .createSourcePathPackage()
+          .createDirectory("org", "example", "first")
           .copyContentsFrom(resourcesDirectory().resolve("first"));
 
       var firstCompilation = compiler.compile(firstWorkspace);
@@ -113,6 +114,7 @@ void compileSourcesToClassesAndProvideThemInClassPathToSecondCompilationWithinJa
       secondWorkspace.addClassPathPackage(firstJar);
       secondWorkspace
           .createSourcePathPackage()
+          .createDirectory("org", "example", "second")
           .copyContentsFrom(resourcesDirectory().resolve("second"));
 
       var secondCompilation = compiler.compile(secondWorkspace);