tests: prevent name clash in variables leading to wrong test name (#8995)
tests: prevent name clash in variables leading to wrong test name (#8995)

running the "geo" unit would have shown that it completed a unit named
"north". this was because the variable `$name` was overwritten.
This commit isn't perfect, but it slightly reduces the chance for
variable name clash.

```
$ ./runtest --single unit/geo
.......
Testing unit/geo
.......
[1/1 done]: north (15 seconds)
```
PKRoma/redis,ofirluzon/redis,charsyam/redis,PKRoma/redis,neomantra/redis,oranagra/redis,antirez/redis,ofirluzon/redis,oranagra/redis,neomantra/redis,PKRoma/redis,antirez/redis,soloestoy/redis,oranagra/redis,PKRoma/redis,charsyam/redis,ofirluzon/redis,oranagra/redis,charsyam/redis,soloestoy/redis,yossigo/redis,antirez/redis,yossigo/redis,charsyam/redis,ofirluzon/redis,yossigo/redis,neomantra/redis,soloestoy/redis,oranagra/redis,yossigo/redis,ofirluzon/redis,yossigo/redis,neomantra/redis,PKRoma/redis,antirez/redis,soloestoy/redis,soloestoy/redis,neomantra/redis,charsyam/redis