[lldb-vscode] correctly handle multiple sourceMap entries

Summary:
`lldb-vscode` concatenates a string of sourceMap entries
specified in the config, but fails to put a space between
each entry, which causes the settings command to fail.
This patch adds a space between each mapping.

Patch by Richard Howell

Differential Revision: https://reviews.llvm.org/D67569

llvm-svn: 373016

lldb/tools/lldb-vscode/lldb-vscode.cpp

@@ -436,7 +436,7 @@ void SetSourceMapFromArguments(const llvm::json::Object &arguments) {
       }
       auto mapFrom = GetAsString((*mapping)[0]);
       auto mapTo = GetAsString((*mapping)[1]);
-      strm << "\"" << mapFrom << "\" \"" << mapTo << "\"";
+      strm << "\"" << mapFrom << "\" \"" << mapTo << "\" ";
     }
   } else {
     if (ObjectContainsKey(arguments, "sourceMap")) {