Import unsafeCoerce# from GHC.Exts
Import unsafeCoerce# from GHC.Exts

This commit changes the 'Data.Text.Array' module from the text benchmark
to import unsafeCoerce# from GHC.Exts, which is backward compatible with
GHC < 9 as well, and it fixes a bunch of tests.

ucsd-progsys/liquidhaskell,ucsd-progsys/liquidhaskell,ucsd-progsys/liquidhaskell,ucsd-progsys/liquidhaskell,ucsd-progsys/liquidhaskell,ucsd-progsys/liquidhaskell