Fix two problems happening during deserialization causing command line defines to be reported as being built-in defines: * When serializing the <built-in> and <command line> files don't convert them into absolute paths. * When deserializing SM_SLOC_BUFFER_ENTRY we need to call setHasLineDirectives in the same way as we do for SM_SLOC_FILE_ENTRY. * When created suggested predefines based on the current command line options we need to add line markers in the same way that InitializePreprocessor does. * Adjust a place in clangd where it was implicitly relying on command line defines being treated as builtin.

Fix two problems happening during deserialization causing command line defines to be reported as being built-in defines: * When serializing or deserializing the <built-in> and <command line> files don't convert them into absolute paths. * When deserializing SM_SLOC_BUFFER_ENTRY we need to call setHasLineDirectives in the same way as we do for SM_SLOC_FILE_ENTRY. * When created suggested predefines based on the current command line options we need to add line markers in the same way that InitializePreprocessor does. * Adjust a place in clangd where it was implicitly relying on command line defines being treated as builtin.

Fix two problems happening during deserialization causing command line defines to be reported as being built-in defines: * When serializing or deserializing the <built-in> and <command line> files don't convert them into absolute paths. * When deserializing SM_SLOC_BUFFER_ENTRY we need to call setHasLineDirectives in the same way as we do for SM_SLOC_FILE_ENTRY. * When created suggested predefines based on the current command line options we need to add line markers in the same way that InitializePreprocessor does. * Adjust a place in clangd where it was implicitly relying on command line defines being treated as builtin.