Dev compiler debugger related tweaks.

tests/lib_strong/html/debugger_test_golden.txt

 Test: List<String> formatting header
 Value:
 [
     "span",
     {
         "style": "background-color: #d9edf7;"
     },
     "JSArray<String> length 3"
 ]
 -----------------------------------
@@ skipping 5871 matching lines @@
 Value:
 [
     "ol",
     {
         "style": "list-style-type: none;padding-left: 0px;margin-top: 0px;margin-bottom: 0px;margin-left: 12px;"
     }
 ]
 -----------------------------------
 Test: Test library Module header
 Value:
-null
+[
+    "span",
+    {
+        "style": "background-color: #d9edf7;"
+    },
+    "Library Module: lib/html/debugger_test"
+]
 -----------------------------------
 Test: Test library Module body
 Value:
 [
     "ol",
     {
         "style": "list-style-type: none;padding-left: 0px;margin-top: 0px;margin-bottom: 0px;margin-left: 12px;"
     },
     [
         "li",
@@ skipping 2904 matching lines @@
                     "object": "<OBJECT>",
                     "config": {
                         "name": "asClass"
                     }
                 }
             ]
         ]
     ]
 ]
 -----------------------------------
-