[LibFuzzer] test_single_input option to run a single test case.

-test_single_input flag specifies a file name with test data.

Review URL: http://reviews.llvm.org/D13359

Patch by Mike Aizatsky!

llvm-svn: 249096
diff --git a/llvm/lib/Fuzzer/FuzzerFlags.def b/llvm/lib/Fuzzer/FuzzerFlags.def
index 824c9f1..3b2a0f5 100644
--- a/llvm/lib/Fuzzer/FuzzerFlags.def
+++ b/llvm/lib/Fuzzer/FuzzerFlags.def
@@ -66,3 +66,4 @@
                                "trace-based-mutations (tbm).")
 FUZZER_FLAG_INT(tbm_width, 5, "Apply at most this number of independent"
                                "trace-based-mutations (tbm)")
+FUZZER_FLAG_STRING(test_single_input, "Use specified file as test input.")
\ No newline at end of file