When matching a line in CMakeCache.txt, ensure A=B and "A"=B are matched (#23745)
Summary:
Currently when reading CMakeCache.txt, only `VAR:TYPE=VAL` can be matched.
This works well for CMake-generated lines, but a user may add a line
without specifying type (`VAR=VAL`), which is totally legitimate in the
eyes of CMake. This improvements in regex ensure that `VAR:TYPE=VAL` is
also matched. The situation of `"VAR":TYPE=VAL` is also corrected.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23745
Differential Revision: D16726514
Pulled By: ezyang
fbshipit-source-id: 6c50150d58926563837cf77d156c24d644666ef0
