Bug fix: remove useless key

In commit d5e89eb9, the test was added with the useless key
"input". Now, after commit 29c37646, the useless key is the key "required".

Inst_eddies/Tests/long_tests.json

@@ -59,7 +59,6 @@
     },
     {
         "input": "&main_nml /\n",
-        "required": ["$src_dir/Inst_eddies/Tests/Input/main_nml.txt"],
         "title": "Extraction_eddies_region_2_noise",
         "command":
 	[