[analyzer] NFC: Remove dead checks when computing DeclStmt construction region.
[analyzer] NFC: Remove dead checks when computing DeclStmt construction region.

In CFG, every DeclStmt has exactly one decl, which is always a variable.

It is also pointless to check that the initializer is the constructor because
that's how construction contexts work now.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@325201 91177308-0d34-0410-b5e6-96231b3b80d8

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