backout 6265036/6531693: causes 6544953

6265036 cv_waituntil_sig() often returns early

6193414 many procfs functions scale badly if a process uses a huge number of VM segments
6246115 MAPSIZE leftover after fix for 4937645
6248701 prgetmap family's initial allocations could be more efficient

OpenSolaris Launch

backout 6265036/6531693: causes 6544953

6265036 cv_waituntil_sig() often returns early

6193414 many procfs functions scale badly if a process uses a huge number of VM segments
6246115 MAPSIZE leftover after fix for 4937645
6248701 prgetmap family's initial allocations could be more efficient

OpenSolaris Launch