Fix lit tests on Windows related to CR+LF

Problem discovered in the breakpoint lit test, but probably exists in others.
lldb-test splits lines on LF.  Input files that are CR+LF separated (as is
common on Windows) then resulted in commands being sent to LLDB that ended
in CR, which confused the command interpreter.

This could be fixed at different levels:

1.  Treat '\r' like a tab or space in the argument splitter.
2.  Fix the line splitters (plural) in lldb-test.
3.  Normalize the test files to LF only.

If we did only 3, I'd expect similar problems to recur, so this patch does
1 and 2.  I may also do 3 in a separate patch later, but that's tricky
because I believe we have some input files that MUST use CR+LF.

Differential Revision: https://reviews.llvm.org/D62759

llvm-svn: 362844