add back check files

Author: Xavientois

tests/init/neg/closureLeak.check

@@ -0,0 +1,7 @@
+-- Error: tests/init/neg/closureLeak.scala:11:14 -----------------------------------------------------------------------
+11 |    l.foreach(a => a.addX(this)) // error
+   |              ^^^^^^^^^^^^^^^^^
+   |              Cannot prove that the value is fully-initialized. May only use initialized value as arguments.
+   |
+   |              The unsafe promotion may cause the following problem:
+   |              Cannot prove that the value is fully initialized. May only use initialized value as arguments.

tests/init/neg/default-this.check

@@ -0,0 +1,5 @@
+-- Error: tests/init/neg/default-this.scala:9:8 ------------------------------------------------------------------------
+9 |        compare() // error
+  |        ^^^^^^^
+  |     Cannot prove that the value is fully initialized. May only use initialized value as arguments. Calling trace:
+  |      -> val result = updateThenCompare(5)	[ default-this.scala:11 ]