Fix build warnings

benchmarks/haskell/Benchmarks/Builder.hs

benchmarks/haskell/Benchmarks/DecodeUtf8.hs

benchmarks/haskell/Benchmarks/FileRead.hs

benchmarks/haskell/Benchmarks/Programs/BigTable.hs

benchmarks/haskell/Benchmarks/Programs/Fold.hs

benchmarks/haskell/Benchmarks/Programs/Sort.hs

benchmarks/haskell/Benchmarks/Pure.hs

src/Data/Text/Internal/Lazy/Encoding/Fusion.hs

tests/Tests/Properties/Builder.hs

tests/Tests/Properties/Instances.hs

tests/Tests/Properties/LowLevel.hs

tests/Tests/Properties/Transcoding.hs

tests/Tests/QuickCheckUtils.hs