Minor, improve test on Java 9 modules

Test that unnamed module does not read unexported package of a named
module

compiler/testData/javaModules/unnamedDependsOnNamed/moduleA/foo/impl/Impl.java

@@ -0,0 +1,3 @@
+package foo.impl;
+
+public class Impl {}

compiler/testData/javaModules/unnamedDependsOnNamed/moduleB.txt

@@ -1 +1,7 @@
-OK
+compiler/testData/javaModules/unnamedDependsOnNamed/moduleB/usage.kt:2:17: error: symbol is declared in module 'moduleA' which does not export package 'foo.impl'
+import foo.impl.Impl
+                ^
+compiler/testData/javaModules/unnamedDependsOnNamed/moduleB/usage.kt:7:5: error: symbol is declared in module 'moduleA' which does not export package 'foo.impl'
+    Impl()  // should be error
+    ^
+COMPILATION_ERROR

compiler/testData/javaModules/unnamedDependsOnNamed/moduleB/usage.kt

@@ -1,5 +1,8 @@
 import foo.Foo
+import foo.impl.Impl
 
 fun usage() {
-    Foo()
+    Foo()  // should be OK
+
+    Impl()  // should be error
 }