Expand Bit array tests (dotnet/corefx#9461)

Expand Bit array tests (dotnet/corefx#9461)

* Make test classes/methods static.
* Add missing data cases, make some cases explicit.
* Expand most data cases, extract bit numbers.
* Split copy type/size tests, add int as type.
* Make sure Get/Set operate over internal boundaries, fix some constant references.
* Extract magic numbers, tweak some test cases.
* Reference to shared definition.
* Extract test data for Not
* Conform test name
* Split operator tests (methods to test aren't data cases).
* Add stress case.
* Two more data cases.
* Correct dataset name, add empty array cases.

Commit migrated from https://github.com/dotnet/corefx/commit/fe2f2b30b6e21cf076c3bc2678cb55c82ad1da8a