Exclude isc_mem_isovermem from ThreadSanitizer
The .is_overmem member of isc_mem_t structure is intentionally accessed unlocked as 100% accuracy isn't necessary here.
Closes #2163 (closed)
The .is_overmem member of isc_mem_t structure is intentionally accessed unlocked as 100% accuracy isn't necessary here.
Closes #2163 (closed)