Add missing insert call for lazy node pattern.

(cherry picked from commit a116ae3)

Author: nirvdrum

src/main/java/org/truffleruby/language/exceptions/SetExceptionVariableNode.java

@@ -48,7 +48,7 @@ public void setLastException(VirtualFrame frame, DynamicObject exception) {
     private GetCurrentRubyThreadNode getCurrentThreadNode() {
         if (getCurrentThreadNode == null) {
             CompilerDirectives.transferToInterpreterAndInvalidate();
-            getCurrentThreadNode = GetCurrentRubyThreadNodeGen.create();
+            getCurrentThreadNode = insert(GetCurrentRubyThreadNodeGen.create());
         }
         return getCurrentThreadNode;
     }