asan: readelf: heap buffer overflow in slurp_hppa_unwind_table

asan: readelf: heap buffer overflow in slurp_hppa_unwind_table

This one isn't just a weird corner case requiring multiple
.PARISC.unwind sections in an object file to trigger the buffer
overflow, it's also a simple bug that would prevent relocations being
applied in the normal case of a single .PARISC.unwind section.

	* readelf (slurp_hppa_unwind_table): Set table_len before use
	in relocation sanity checks.