convert Select Case [object] using Operators.ConditionalCompareObject...

[TymurGubayev]

Problem

#1100: Select Case [object] can have incorrect converted code

Solution

• Any comments on the approach taken, its consistency with surrounding code, etc.
  GetFullExpressionForVbObjectComparison now has a ComparisonKind parameter (new enum).
  VisitSelectBlock now checks if expression type is object first, in which case different code is generated.
• Which part of this PR is most in need of attention/improvement?
  • ComparisonKind has Unknown value, which might not be necessary - I added it in case something goes terribly wrong.
  • ComparisonAdjustedForStringComparison() (renamed from EqualsAdjustedForStringComparison()) has return SyntaxFactory.BinaryExpression(GetSyntaxKind(comparisonKind), csLeft, csRight); for the non-Object case. With how the code currently looks like, the comparisonKind will always be Equals here (i.e. the call to GetSyntaxKind(comparisonKind) is unnecessary). I've added it for completeness sake, because otherwise the method could return unexpected ExpressionSyntax should it ever be used somewhere else.
• At least one test covering the code changed