[llvm] [llvm-profdata] Disable -all-functions by default (PR #138105)

[Teresa Johnson via llvm-commits]

teresajohnson wrote:

Adding an FDO developer for thoughts. It looks like -all-functions is already disabled by default, the issue is that it is essentially ignored if the `-function=` function filter option is not specified. I'm not sure if it has always been that way, but I think the code change makes sense (and I think line 3018 should probably be changed similarly?). That being said, if the default has always been to show all functions, it might make sense to make this code change but *also* flip the -all-functions default to true to maintain the status quo (but then the code change here fixes the issue where -all-functions=false would do nothing without -function= ). I would like @xur-llvm 's opinion on this though.

https://github.com/llvm/llvm-project/pull/138105