[asan_symbolize] Fix bug where the frame counter was not incremented.

Summary:
This bug occurred when a plug-in requested that a binary not be
symbolized while the script is trying to symbolize a stack frame. In
this case `self.frame_no` would not be incremented. This would cause
subsequent stack frames that are symbolized to be incorrectly numbered.

To fix this `get_symbolized_lines()` has been modified to take an
argument that indicates whether the stack frame counter should
incremented. In `process_line_posix()` `get_symbolized_lines(None, ...)`
is now used in in the case where we don't want to symbolize a line so
that we can keep the frame counter increment in a single function.

A test case is included. The test uses a dummy plugin that always asks
`asan_symbolize.py` script to not symbolize the first binary that the
script asks about. Prior to the patch this would cause the output to
script to look something like

```
  #0 0x0
  #0 0x0 in do_access
  #1 0x0 in main
```

rdar://problem/49476995

Reviewers: kubamracek, yln, samsonov, dvyukov, vitalybuka

Subscribers: #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D65495

llvm-svn: 368373