Fix SpecCPU2017's dependency from timeit-target to build-timeit-target
Building SpecCPU2017 using cmake raises this error:
```
CMake Error at External/SPEC/SpecCPU2017.cmake:263 (add_dependencies):
The dependency target "timeit-target" of target "imagevalidate_525-target"
does not exist.
Call Stack (most recent call first):
External/SPEC/CINT2017rate/525.x264_r/CMakeLists.txt:24 (speccpu2017_validate_image)
```
I think `timeit-target` should be `build-timeit-target` instead because cmake's progress output has this line:
```
[ 3%] Built target build-timeit-target
```
Fixing this resolves the dependency error.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D100734
1 file changed
