Checks in JSON output reference wrong source file paths

In some cases, Mopsa's JSON output prefixes the source file path in reported checks with patched-

For example, for the source file sv-benchmarks/c/busybox-1.22.0/who-1.i, the corresponding checks are reported as:

"kind": "safe",
"title": "Integer overflow",
"messages": "",
"range": {
    "start": {
        "file": "/home/holterka/sv-benchmarks/c/busybox-1.22.0/patched-who-1.i",
        "line": 2996,
        "column": 127
    },
    "end": {
        "file": "/home/holterka/sv-benchmarks/c/busybox-1.22.0/patched-who-1.i",
        "line": 2996,
        "column": 146
    }
},