Don't use goroutines in SetValue

[Marreck]

Removed the use of goroutines in SetValue.

My guess is that these made sense when bitmap adding was less efficient. Now they add unnecessary overhead.

Also added a check to make sure bits in their respective bitmaps are only unset for those where columnID is in the existence bitmap.

With goroutines:

goos: windows
goarch: amd64
pkg: github.com/RoaringBitmap/roaring/BitSliceIndexing
cpu: 12th Gen Intel(R) Core(TM) i5-12600K
BenchmarkSetRoaring
BenchmarkSetRoaring-16            157240              8431 ns/op
PASS

Without goroutines:

goos: windows
goarch: amd64
pkg: github.com/RoaringBitmap/roaring/BitSliceIndexing
cpu: 12th Gen Intel(R) Core(TM) i5-12600K
BenchmarkSetRoaring
BenchmarkSetRoaring-16           2262295               498.2 ns/op
PASS

[lemire]

Sounds good. Let us run the tests.

[lemire]

There is a failing test, but it is not related to this PR, I expect.

Merging.