This is the runtime equivalent of JDK-8267583.

To reproduce:

> unzip greetings.zip
> javac -d bin/com.greetings src/com.greetings/module-info.java src/com.greetings/com/greetings/Main.java
> java -p bin -m com.greetings/com.greetings.Main
Greetings!
> mv bin/com.greetings/com/greetings/Main.class target; ln -s $PWD/target/Main.class bin/com.greetings/com/greetings/Main.class
> java -p bin -m com.greetings/com.greetings.Main
Error occurred during initialization of boot layer
java.lang.module.FindException: Error reading module: bin/com.greetings
Caused by: java.lang.module.InvalidModuleDescriptorException: Package com.greetings not found in module