Fix setproctitle related crashes. (#8150)
Fix setproctitle related crashes. (#8150)

Makes spt_init more careful with assumptions about what memory regions
may be overwritten. It will now only consider a contiguous block of argv
and envp elements and mind any gaps.
ctripcorp/redis,ofirluzon/redis,PKRoma/redis,yossigo/redis,soloestoy/redis,yossigo/redis,antirez/redis,yossigo/redis,ofirluzon/redis,ctripcorp/redis,oranagra/redis,charsyam/redis,neomantra/redis,neomantra/redis,antirez/redis,charsyam/redis,neomantra/redis,oranagra/redis,charsyam/redis,oranagra/redis,ctripcorp/redis,oranagra/redis,yossigo/redis,ofirluzon/redis,soloestoy/redis,neomantra/redis,PKRoma/redis,charsyam/redis,antirez/redis,charsyam/redis,yossigo/redis,PKRoma/redis,soloestoy/redis,oranagra/redis,PKRoma/redis,PKRoma/redis,ofirluzon/redis,soloestoy/redis,soloestoy/redis,neomantra/redis,ofirluzon/redis,ctripcorp/redis,antirez/redis