Merging r366985:

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r366985 | labath | 2019-07-25 08:38:33 +0200 (Thu, 25 Jul 2019) | 16 lines

LLGS: fix tracking execve on linux

Summary:
Due to a logic error, lldb-server ended up asserting/crashing every time
the debugged process attempted an execve(). This fixes the error, and
extends TestExec to work on other platforms too. The "extension"
consists of avoiding non-standard posix_spawn extensions and using the
classic execve() call, which should be available on any platform that
actually supports re-execing. I change the test decorator from
@skipUnlessDarwin to @skipIfWindows.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D65207
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llvm-svn: 367128