thcrap: Small improvement to new exception logging
thcrap: Small improvement to new exception logging

Fixes a pointer offset error that prevented logging the bottom of the stack, adds a failsafe to detect nonsensical ESP values, and allows manual stack walk to be run while only dumping calls/returns.
thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap