Remove benchmarks for Mul to scrap vector dependency - mul is O(1) anyway and never on a critical path

* Support only GHC >= 8.0

* Fix a build warning

* Make integer-simple flag redundant

Kubo Kovac authored 7 years ago and Herbert Valerio Riedel committed 6 years ago

if we only need to run a few benchmarks,
e.g. `text-benchmarks Pure/drop/Text+tiny`
it's wasteful to initialize all of them
(and read all the test data in memory - all
the test data is a few hundreds of MB, but
we read it in several tests, as different types,
and most seriously, as String - which turns this
into GBs of memory)

I used the code from the gist as the source for the Concat module.

Benchmarks to:
1) prove that stream after unstream fusion works
2) measure the overhead of stream followed by unstream

Progress towards gh-81.

--HG--
extra : rebase_source : 0559da50e2b5d43f46e4c4baa9f4b5457e8781da
extra : amend_source : 1c20c33aa19bece776361953371efc46d0ec236e
extra : histedit_source : a7aba7dd23ae5f886fd41e3f0856da129165c878

Since encodeUtf8_2 wins under all circumstances, there's no reason
to keep the intermediate version around.

Not surprisingly, this is a lot faster than encodeUtf8_1 and the
Builder-based rewrite under almost all circumstances.

It's slower on tiny inputs (20%), but roughly twice as fast as
encodeUtf8_1 on longer inputs.

--HG--
extra : amend_source : 093410e1295572be039d87a9c21e97d250c5f9f9

--HG--
rename : Data/Text/Lazy/Encoding/Fusion.hs => Data/Text/Internal/Lazy/Encoding/Fusion.hs
rename : Data/Text/Lazy/Fusion.hs => Data/Text/Internal/Lazy/Fusion.hs
rename : Data/Text/Lazy/Search.hs => Data/Text/Internal/Lazy/Search.hs
extra : amend_source : 2c28ab48f28c6a5750a180a503e1efec634253ea

This provides a nice performance boost!