Load automatic module names correctly

Load the Automatic-Module-Name manifest entry value if it's present (see
http://mail.openjdk.java.net/pipermail/jpms-spec-observers/2017-May/000877.html),
otherwise sanitize the name of the .jar file, throwing out all chars
except alphanumeric, duplicate dots and a version qualifier

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

@@ -0,0 +1,4 @@
+module main {
+    requires auto.mat1c.m0d.ule;
+    requires automodule2;
+}