Also checking line end when block structure is filtered

[Cosifne]

Fix https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2094051

Reason:
In PR #71064, it introduced a trick to only fold the inner method2 in this case:

Method1(Method2(
))

Method1's block is skipped because it has the same start line as Method2

However this introduce problem because in this case

        If str.Contains("foo") Then

        End If

In VB, we first provide the block structure of If, also we provide the block structure for foo because it is a string literal https://github.com/dotnet/roslyn/blob/release/dev17.10/src/Features/CSharp/Portable/Structure/Providers/StringLiteralExpressionStructureProvider.cs

Because foo and If statement both have the same start line, If statement is removed from the block structure span.

Later, because foo's structure is removed because its start line and end line are same.

roslyn/src/EditorFeatures/Core/Structure/AbstractStructureTaggerProvider.cs

Line 263 in fa643d6

if (startLine != endLine)

Fix:
Instead of only checking for the start line, also check the end line when trying to remove the block. It should still work for case

Method1(Method2(
))

the block structure of Method1 would still be removed. and it's safer when dealing with other cases.

Before:

After:

[CyrusNajmabadi]

Can you show a picture showing how the user experience has changed? Thanks!

[Cosifne]

Can you show a picture showing how the user experience has changed? Thanks!

Editing now...

[Cosifne]

Reset this to its prev state: see https://github.com/dotnet/roslyn/pull/71064/files#diff-0fd1ed24f6843351146536bd47576962e5ff059c6a5834075c2d7beef4b50cbc