Factorize a bit more some symbol handling code.

pointer value, be sure to have the relevant insn ptr value when
fetching the stack frames (spotted by Peter Oberndorfer).

(regression spotted by Peter Oberndorfer).

pointer value, be sure to always store it (spotted by Peter
Oberndorfer).

current frame for some of the registers we know of (frame pointer,
stack pointer).

ole32: Add tests for invalid clipformat/tymed combinations in IOleCache:Cache and for caching formats with a clipformat of 0.

ole32: In the data cache, fmtetc->cfFormat and fmtetc->tymed can be 0 which means to match any clipformat/tymed.

Therefore, keep the clipformat of the data in the data_cf field.
Return an error from SetData if a non-zero clipformat hasn't been specified.
Write out stgmedium.tymed instead of fmtetc.tymed, which is guaranteed 
to be non-zero if data has been set.

ole32: Check that the specified clipboard format and tymed are valid in IOleCache::Cache in the data cache.