Java: Add an upgrade script

Author: igfoo

java/ql/lib/upgrades/37f33da42d2cffa6ad8b26feaa6beed1c5ce3149/compilations.ql

@@ -0,0 +1,7 @@
+class Compilation extends @compilation {
+  string toString() { none() }
+}
+
+from Compilation c, string cwd
+where compilations(c, cwd)
+select c, 1, /* Java compilation */ cwd, "<unnamed compilation>"