Fix MLIR Location in de-serialization

* Add mlir::NameLoc with mlir::FileLineColLoc as ChildLoc to preserve
locations across serialize-deserialize iterations.
* Add location information to test files and aprropriate CHECK commands

Signed-off-by: Udaya Ranga <udaya.ranga@arm.com>
Change-Id: I48725f9c354e1bacd76b20c137e58a1b63059e70
(cherry picked from commit 67fbed32eeca2153ff7114a348d4cabd4d889ad3)