Formatting cmake (to lowercase without space for if/elseif/else/endif) (#35521)
Summary:
Running commands:
```bash
shopt -s globstar
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i CMakeLists.txt
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i caffe2/**/CMakeLists.txt
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i torch/**/CMakeLists.txt
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i c10/**/CMakeLists.txt
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i cmake/**/*.cmake
sed -e 's/IF (/if(/g' -e 's/IF(/if(/g' -e 's/if (/if(/g' -e 's/ELSE (/else(/g' -e 's/ELSE(/else(/g' -e 's/else (/else(/g' -e 's/ENDif(/endif(/g' -e 's/ELSEif(/elseif(/g' -i cmake/**/*.cmake.in
```
We may further convert all the commands into lowercase according to the following issue: https://gitlab.kitware.com/cmake/cmake/commit/77543bde41b0e52c3959016698b529835945d62d.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35521
Differential Revision: D20704382
Pulled By: malfet
fbshipit-source-id: 42186b9b1660c34428ab7ceb8d3f7a0ced5d2e80
