Fix TestBreakpointSerialization on windows

The test exposed a bug in the StructuredData Serialization code, which did not
escape the backslash properly. This manifested itself as windows breakpoint
serialization roundtrip test not succeeding (as windows paths included
backslashes).

llvm-svn: 282167
diff --git a/lldb/source/Core/StructuredData.cpp b/lldb/source/Core/StructuredData.cpp
index 3866861..46be782 100644
--- a/lldb/source/Core/StructuredData.cpp
+++ b/lldb/source/Core/StructuredData.cpp
@@ -264,7 +264,7 @@
   const size_t strsize = m_value.size();
   for (size_t i = 0; i < strsize; ++i) {
     char ch = m_value[i];
-    if (ch == '"')
+    if (ch == '"' || ch == '\\')
       quoted.push_back('\\');
     quoted.push_back(ch);
   }