Fix lit tests on Windows related to CR

[amccarth]

Summary

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.

lldb/source/Utility/Args.cpp

ParseSingleArgument(llvm::StringRef command) {
   // like: "Hello "world'!' (which will make a single argument "Hello world!")
   // we remember the first quote character we encounter and use that for the
   // quote character.
   char first_quote_char = '\0';
 
   bool arg_complete = false;
   do {
     // Skip over over regular characters and append them.
-    size_t regular = command.find_first_of(" \t\"'`\\");
+    size_t regular = command.find_first_of(" \t\r\"'`\\");
     arg += command.substr(0, regular);
     command = command.substr(regular);
 
     if (command.empty())
       break;
 
     char special = command.front();
     command = command.drop_front();
case '\\':
 
       arg += command.front();
       command = command.drop_front();
 
       break;
 
     case ' ':
     case '\t':
+    case '\r':
       // We are not inside any quotes, we just found a space after an argument.
       // We are done.
       arg_complete = true;
       break;
 
     case '"':
     case '\'':
     case '`':

lldb/tools/lldb-test/lldb-test.cpp

int opts::breakpoint::evaluateBreakpoints(Debugger &Dbg) {
   std::unique_ptr<MemoryBuffer> MB = opts::openFile(breakpoint::CommandFile);
 
   LinePrinter P(4, outs());
   StringRef Rest = MB->getBuffer();
   int HadErrors = 0;
   while (!Rest.empty()) {
     StringRef Line;
     std::tie(Line, Rest) = Rest.split('\n');
-    Line = Line.ltrim();
+    Line = Line.ltrim().rtrim();
     if (Line.empty() || Line[0] == '#')
       continue;
 
     if (!Persistent)
       Target->RemoveAllBreakpoints(/*internal_also*/ true);
 
     std::string Command = substitute(Line);
     P.formatLine("Command: {0}", Command);
int opts::irmemorymap::evaluateMemoryMapCommands(Debugger &Dbg) {
   IRMemoryMapTestState State(Target);
 
   // Parse and apply commands from the command file.
   std::unique_ptr<MemoryBuffer> MB = opts::openFile(irmemorymap::CommandFile);
   StringRef Rest = MB->getBuffer();
   while (!Rest.empty()) {
     StringRef Line;
     std::tie(Line, Rest) = Rest.split('\n');
-    Line = Line.ltrim();
+    Line = Line.ltrim().rtrim();
 
     if (Line.empty() || Line[0] == '#')
       continue;
 
     if (evalMalloc(Line, State))
       continue;
 
     if (evalFree(Line, State))