[libFuzzer] Fix sizeof(ptr) bug.
[libFuzzer] Fix sizeof(ptr) bug.

sizeof(const char *) returns 4 or 8 when what we really want is the size
of the array.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@323802 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt