[code coverage] Remove fuzzer corpus as a dependency

The coverage builder doesn't run fuzzers anymore, and the corpus has
been turned down, therefore, this CL removes the dependency between
libfuzzer and the fuzzer corpus.

Bug: 990387
Change-Id: I07cbec6629903aa3f2f5b53d3e7692a1e65acca3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1891010Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710949}

testing/libfuzzer/fuzzer_test.gni

@@ -220,11 +220,6 @@ template("fuzzer_test") {
       if (is_mac) {
         sources += [ "//testing/libfuzzer/libfuzzer_exports.h" ]
       }
-
-      # Used to isolate fuzzer corpus and run fuzzer targets on swarming.
-      data = [
-        "//testing/libfuzzer/fuzzer_corpus_for_bots/${target_name}/",
-      ]
     }
   } else {
     # noop on unsupported platforms.