OS X symbolization still does not work

### What version of pprof are you using?

fe62a0baab87ba3abca12f4a621532bf67c9a7d2

### What operating system and processor architecture are you using?

OS X Mojave

### What did you do?

```
$ which addr2line
/usr/local/bin/addr2line
$ cat test.cpp
#include
#include

int main() {
std::vector x(10000000, 2);
for (int i = 0; i < 100000; i++) {
x[i] *= x[(i+200) % 1000];
}
x.resize(1000000000);
std::cerr << x[123] << "\n";
}

$ clang++ test.cpp -g3 -fno-pie -ltcmalloc
$ HEAPPROFILE=/tmp/hh ./a.out
Starting tracking the heap
Dumping heap profile to /tmp/hh.0001.heap (3852 MB allocated cumulatively, 3852 MB currently in use)
4
Dumping heap profile to /tmp/hh.0002.heap (Exiting, 0 bytes in use)
$ pprof a.out /tmp/hh.0001.heap
Using local file a.out.
Using local file /tmp/hh.0001.heap.
Welcome to pprof! For help, type 'help'.
(pprof) top
Total: 3852.8 MB
3852.8 100.0% 100.0% 3852.8 100.0% 0x00007fff64e72c05
```

### What did you expect to see?

Expected address to be symbolized

### What did you see instead?

Not symbolized