Can't mute platform select command.
UNSUPPORTED: remote-linux
RUN: echo start >%t.file
RUN: %lldb -x -b --source-quietly -s %S/Inputs/EchoCommandsTest.in >>%t.file
RUN: echo done >>%t.file
RUN: FileCheck  %S/Inputs/EchoCommandsQuiet.out <%t.file