Disable exit-on-SIGPIPE in lldb

Occasionally, during test teardown, LLDB writes to a closed pipe.
Sometimes the communication is inherently unreliable, so LLDB tries to
avoid being killed due to SIGPIPE (it calls `signal(SIGPIPE, SIG_IGN)`).
However, LLVM's default SIGPIPE behavior overrides LLDB's, causing it to
exit with IO_ERR.

Opt LLDB out of the default SIGPIPE behavior. I expect that this will
resolve some LLDB test suite flakiness (tests randomly failing with
IO_ERR) that we've seen since r344372.


Differential Revision: https://reviews.llvm.org/D69148

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375288 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed