Problem: memory leaks on windows when querying views.
The problem was the local 'view_lex' in mysql_make_view() which is
allocated in a MEM_ROOT, and never destroyed
(it is used later, and cannot be destroyed)

Regression source is patch for:
Bug#13901905 - CRASH: INSERT ON DUPLICATE KEY UPDATE READS FREED MEMORY

Fix:
Make LEX::insert_update_values_map private, with accessor functions.
Make it a pointer, and initialize the std::map on demand, rather than
up-front (it is used in only rare cases anyways).
Clear and delete it in lex_end()

Also fix broken build on windows with -DWITH_MSCRT_DEBUG=1
 - rename Path::getcwd() to Path::path_getcwd()
 - remove Protocol_local::free(), it was unused