Make constructor names in info tables position independent

Make constructor names in info tables position independent

Info tables, like everything else in the text section, MUST NOT contain
pointers. A pointer is, by definition, position dependent and is therefore
fundamentally incompatible with generating position independent code.

Therefore, we have to store an offset from the info label to the string
instead of the pointer, just as we already did for other things referred
to by the info table (SRTs, large bitmaps, etc.)