input_chunk: Use the different storage.path per tests

This is because different storage.paths should be used per test.
Sometimes this cause failure for retrieving the file contents to prepare
the data for test cases:

```log
Test input_chunk_exceed_limit...                [ FAILED ]
  input_chunk.c:91: Check getting output file content: ~/GitHub/fluent-bit/tests/internal/data/input_chunk/out/a_thousand_plus_one_bytes.out... failed
[2023/07/28 00:03:09] [error] [~/GitHub/fluent-bit/tests/internal/input_chunk.c:56 errno=0] Success
```

After splitting the storage.path per test case, this error won't happen.

Signed-off-by: Hiroshi Hatake <[email protected]>

tests/internal/input_chunk.c

@@ -162,6 +162,7 @@ void do_test(char *system, const char *target, ...)
     int out_ffd;
     char path[PATH_MAX];
     struct tail_test_result result = {0};
+    char storage_path[PATH_MAX];
 
     result.nMatched = 0;
     result.target = target;
@@ -175,10 +176,12 @@ void do_test(char *system, const char *target, ...)
 
     ctx = flb_create();
 
+    snprintf(storage_path, sizeof(storage_path), "/tmp/input-chunk-test-%s", target);
+
     /* create chunks in /tmp folder */
     ret = flb_service_set(ctx,
                           "Parsers_File", DPATH "parser.conf",
-                          "storage.path", "/tmp/input-chunk-test/",
+                          "storage.path", storage_path,
                           "Log_Level", "error",
                           NULL);
     TEST_CHECK_(ret == 0, "setting service options");