Incorrect stack trace for stripped binaries

[xppt]

If the executable is stripped, I expect the FailureSignalHandler to dump module+offset for each stack frame, but the output is always (unknown). Seems like this is because of a typo in OpenObjectFileContainingPcAndGetStartAddress.

Code to reproduce: repro.zip Just extract and run ./run_test.py on the host (docker and python3 are required).

Expected output

    @     0x7fa3c2b86699 __cxa_throw
    @     0x55a4ed24f389 (/build/testbin-stripped+0x2388)
    @     0x55a4ed24f3c6 main

Actual output

    @     0x7f81b4790699 __cxa_throw
    @     0x5645b9032389 (unknown)
    @     0x5645b90323c6 main

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 64.41%. Comparing base (c0813f9) to head (78484ce).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1092 +/- ## ========================================== + Coverage 63.56% 64.41% +0.85% ========================================== Files 19 19 Lines 2566 2563 -3 Branches 910 909 -1 ========================================== + Hits 1631 1651 +20 + Misses 676 647 -29 - Partials 259 265 +6 ``` | [Files](https://app.codecov.io/gh/google/glog/pull/1092?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=google) | Coverage Δ | | |---|---|---| | [src/symbolize.cc](https://app.codecov.io/gh/google/glog/pull/1092?src=pr&el=tree&filepath=src%2Fsymbolize.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=google#diff-c3JjL3N5bWJvbGl6ZS5jYw==) | `63.75% <100.00%> (+7.22%)` | :arrow_up: | ... and [3 files with indirect coverage changes](https://app.codecov.io/gh/google/glog/pull/1092/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=google)

[xppt]

Also, what's the output with your changes?

The stack trace contains module+offset line after patching:

    @     0x7fde6810f699 __cxa_throw
    @     0x55ce95d3d389 (/build/testbin-stripped+0x2388)
    @     0x55ce95d3d3c6 main

[sergiud]

Thank you!