Issue Description:

Failure of test case SwiftREPL/ErrorReturn.test on PPC64LE while building Apple Swift 5 toolchain.

• • • • • • • • • • TEST 'LLDB :: SwiftREPL/ErrorReturn.test' FAILED ********************
                    Script:

                    : 'RUN: at line 3'; /home/sar/swift-source/build/buildbot_linux/lldb-linux-powerpc64le/bin/lldb -S /home/sar/swift-source/lldb/lit/lit-lldb-init --repl < /home/sar/swift-source/lldb/lit/SwiftREPL/ErrorReturn.test | /home/sar/swift-source/build/buildbot_linux/llvm-linux-powerpc64le/bin/FileCheck /home/sar/swift-source/lldb/lit/SwiftREPL/ErrorReturn.test

                    Exit Code: 1

Command Output (stderr):

Execution interrupted. Enter code to recover and continue.
Enter LLDB commands to investigate (type :help for assistance.)
/home/sar/swift-source/lldb/lit/SwiftREPL/ErrorReturn.test:9:11: error: CHECK: expected string not found in input
// CHECK: $E0: VagueProblem = SomethingWentWrong
^
<stdin>:1:1: note: scanning from here
Welcome to Swift version 5.0-dev (LLVM 40e9a1bc2b, Swift 52ddabe).
^
<stdin>:5:10: note: possible intended match here

• thread [DON'T MERGE] Test pull request #1, name = 'repl_swift'
  ^

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