Bump bytestring submodule to something closer to 0.12.1

...mostly so that 16d6b7e835ffdcf9b894e79f933dd52348dedd0c
(which reworks unaligned writes in Builder) and the stuff in
haskell/bytestring#631 can see wider testing.

The less-terrible code for unaligned writes used in Builder on
hosts not known to be ulaigned-friendly also takes less effort
for GHC to compile, resulting in a metric decrease for T21839c
on some platforms.

The metric increase on T21839r is caused by the unrelated commit
750dac33465e7b59100698a330b44de7049a345c.  It perhaps warrants
further analysis and discussion (see #23822) but is not critical.

Metric Decrease:
T21839c
Metric Increase:
T21839r

testsuite/tests/ghc-api/all.T

@@ -1,7 +1,7 @@
 setTestOpts(when(arch('wasm32'), run_timeout_multiplier(2)))
 
 test('ghcApi', normal, compile_and_run, ['-package ghc'])
-test('T6145', js_broken(22352), makefile_test, ['T6145'])
+test('T6145', normal, makefile_test, ['T6145'])
 test('T8639_api', req_rts_linker,
               makefile_test, ['T8639_api'])
 test('T8628', req_rts_linker,

testsuite/tests/ghc-api/annotations-literals/all.T

@@ -1,2 +1,2 @@
-test('literals', [normalise_slashes, extra_files(['LiteralsTest.hs']), js_broken(22352)], makefile_test, ['literals'])
-test('parsed', [extra_files(['LiteralsTest2.hs']), js_broken(22352)], makefile_test, ['parsed'])
+test('literals', [normalise_slashes, extra_files(['LiteralsTest.hs'])], makefile_test, ['literals'])
+test('parsed', [extra_files(['LiteralsTest2.hs'])], makefile_test, ['parsed'])

testsuite/tests/ghci/scripts/T9881.stdout

@@ -1,7 +1,7 @@
 type Data.ByteString.Lazy.ByteString :: *
 data Data.ByteString.Lazy.ByteString
   = Data.ByteString.Lazy.Internal.Empty
-  | Data.ByteString.Lazy.Internal.Chunk {-# UNPACK #-}Data.ByteString.ByteString
+  | Data.ByteString.Lazy.Internal.Chunk {-# UNPACK #-}StrictByteString
                                         Data.ByteString.Lazy.ByteString
   	-- Defined in ‘Data.ByteString.Lazy.Internal’
 instance Monoid Data.ByteString.Lazy.ByteString
@@ -19,19 +19,19 @@ instance Ord Data.ByteString.Lazy.ByteString
 
 type Data.ByteString.ByteString :: *
 data Data.ByteString.ByteString
-  = bytestring-0.11.4.0:Data.ByteString.Internal.Type.BS {-# UNPACK #-}(GHC.ForeignPtr.ForeignPtr
+  = bytestring-0.12.1.0:Data.ByteString.Internal.Type.BS {-# UNPACK #-}(GHC.ForeignPtr.ForeignPtr
                                                                           GHC.Word.Word8)
                                                          {-# UNPACK #-}Int
-  	-- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  	-- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Monoid Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Read Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Semigroup Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Show Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Eq Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’
 instance Ord Data.ByteString.ByteString
-  -- Defined in ‘bytestring-0.11.4.0:Data.ByteString.Internal.Type’
+  -- Defined in ‘bytestring-0.12.1.0:Data.ByteString.Internal.Type’