Make '^' operation nodes internal

[agocke]

We plan to mark this as a non-user overridable unary operator in a later release, so this node should not be in the public API.

[agocke]

FYI @jaredpar for shiproom

[jcouv]

Looks like some tests need to be updated:

2019-01-29T22:23:10.0853646Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.VerifyIndexOperator_Int [FAIL]
2019-01-29T22:23:10.0854336Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.VerifyRangeOperator_NullableInt_Create_WithHat [FAIL]
2019-01-29T22:23:10.0854812Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.FromEndIndexFlow_01 [FAIL]
2019-01-29T22:23:10.0855082Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.VerifyIndexOperator_NullableInt [FAIL]
2019-01-29T22:23:10.0855193Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.VerifyIndexOperator_ConvertibleToInt [FAIL]
2019-01-29T22:23:10.0855360Z     Microsoft.CodeAnalysis.CSharp.UnitTests.IOperationTests.VerifyRangeOperator_Int_Create_WithHat [FAIL]

[AlekseyTs]

FromEndIndex = 0x64, [](start = 8, length = 20)

Perhaps keep this as a comment, or add a comment indicating that the value is available for reuse #Closed

[AlekseyTs]

Done with review pass (iteration 1) #Closed

[AlekseyTs]

Please make sure this change does not introduce new failures when tests are run with IOperation hook enabled. #Closed

[agocke]

@AlekseyTs Done. I ran build -testIOperation and I saw a number of failures, but it doesn't look like this introduces any new ones.

[AlekseyTs]

LGTM (iteration 2)

[agocke]

@jaredpar Can we take this PR to make the IFromEndOperation nodes internal in preview 4? These nodes will be removed before RTM (#33155)

[jaredpar]

Yes but get it in soon. We're snappnig I imagine tomorrow night.

[agocke]

@jaredpar This is ready, if I'm good to merge