JVM: add tests on some JPMS-related diagnostics

Somehow we ended up in the state where we have two diagnostics which are
not covered by any tests in the project. This commit adds simple tests
for them.

 #KT-60797

compiler/testData/javaModules/noDependencyOnUnnamed/main/module-info.java

@@ -0,0 +1,3 @@
+module main {
+    requires kotlin.stdlib;
+}