Always treat all sources as parts of the module being compiled

If a path to the module-info.java file is passed as an argument, we
should treat all other source files passed as arguments (either as
individual source files or inside a source directory) as members of that
module. Previously we treated other source files as members of the
unnamed module, and this resulted in incorrect errors when using a
member exported with a qualification from another named module, for
example

 #KT-18598 In Fixed

compiler/testData/javaModules/specifyPathToModuleInfoInArguments/moduleA/unexported/Unexported.java

@@ -0,0 +1,3 @@
+package unexported;
+
+public class Unexported {}