shell32: Make sure BrowseForFolder doesn't return NULL for the Desktop folder as this means a cancel.

shell32/tests: ILFree() and ILIsEqual() are exported by ordinal only on Win9x. So use GetProcAddress().

Unless specified otherwise they are implemented by a '__regs_' function.
Keep track of the '-i386' flag so we can detect CONTEXT* vs. CONTEXT86* mismatches.
Remove an unneeded and broken hack meant to fudge the number of parameters.