[lld] [LLD][COFF] Move delay IAT into its own .didat section. (PR #137100)

[via llvm-commits]

kkent030315 wrote:

> It is recommended that protected delay load be enabled by default if CFG is enabled.
> https://learn.microsoft.com/en-us/windows/win32/secbp/pe-metadata

Also, the official doc quote above is a bit misleading IMO. It is mixing up with control flow guard (CFGuard or CFG here), which is completely irrevelant in terms of CFG. The purpose of emitting `.didat` section in its own section is to let Windows loader change the protection safely (as per MS doc say).

https://github.com/llvm/llvm-project/pull/137100