Fix: Duplicated test name when local time = UTC
Fix: Duplicated test name when local time = UTC

local offset = 0:
Test `DateTime(Local),TimeSpan.FromHours(0))` was adjusted to `-1min`.
But there's already a test with `-1min` (`TimeSpan.FromSeconds(-60)`)
-> both tests have same generated name

Now: Instead of adjusting test offset, keep it and adjust expected
result.
-> in case of local offset in tested offsets:
`DateTime(Local), TimeSpan.FromHours(XXX)` is same test as
`offset = localOffset (XXX) succeeds`.
Still keep both because a) easier to implement b) keeps test count same

fable-compiler/Fable,fable-compiler/Fable,ncave/Fable,ncave/Fable,fable-compiler/Fable,ncave/Fable,fable-compiler/Fable,fable-compiler/Fable,ncave/Fable,ncave/Fable,fable-compiler/Fable,ncave/Fable,fable-compiler/Fable,ncave/Fable