[CFG]

After discussion with Zhongxing, don't force the initializer of DeclStmts to be
block-level expressions.

This led to some interesting fallout:

[UninitializedValues]

Always visit the initializer of DeclStmts (do not assume they are block-level expressions).

[BasicStore]

With initializers of DeclStmts no longer block-level expressions, this causes self-referencing initializers (e.g. 'int x = x') to no longer cause the initialized variable to be live before the DeclStmt.  While this is correct, it caused BasicStore::RemoveDeadBindings() to prune off the values of these variables from the initial store (where they are set to uninitialized).  The fix is to back-port some (and only some) of the lazy-binding logic from RegionStore to
BasicStore.  Now the default values of local variables are determined lazily as opposed
to explicitly initialized.

llvm-svn: 97591