Fixed some unit-tests that were relying on an implicit definition of "_" at the top of the file. (#886)

* Added missing [SkippableFact] attribute to prevent test from failing instead of being skipped.
* Fix failing unit-tests that used an aliased member which defaults to handling upper case/lower case keys differently.

Previously, sequence of keys were interpreted using a language hack at the top of the file.
The "using _ = Keys;" statement defaulted to a class that contained both "K" and "ucK" for lower-case 'K' and upper-case 'K' respectively.
Now, "_" is a member of the class that points to a "KbdLayout" class with members "k" and "K" respectively.

Therefore, the unit-test was broken when the definition of "_" changed.

Author: springcomp

test/MovementTest.VI.Multiline.cs

@@ -58,7 +58,7 @@ public void ViMoveToFirstLogicalLine_MustDing_ForSingleLine()
             ViJumpMustDing(buffer, keys);
         }
 
-        [Fact]
+        [SkippableFact]
         public void ViMoveToFirstNonBlankOfLogicalLineThenJumpToEndOfLogicalLine()
         {
             TestSetup(KeyMode.Vi);
@@ -77,7 +77,7 @@ public void ViMoveToFirstNonBlankOfLogicalLineThenJumpToEndOfLogicalLine()
                 ));
         }
 
-        [Fact]
+        [SkippableFact]
         public void ViMoveToFirstNonBlankOfLogicalLine_NoOp_OnEmptyLine()
         {
             TestSetup(KeyMode.Vi);
@@ -87,13 +87,13 @@ public void ViMoveToFirstNonBlankOfLogicalLine_NoOp_OnEmptyLine()
             const string buffer = "\"\n\n\"";
 
             Test(buffer, Keys(
-                _.DQuote, _.Enter, _.Enter, _.DQuote, _.Escape, _.K,
+                _.DQuote, _.Enter, _.Enter, _.DQuote, _.Escape, _.k,
                 CheckThat(() => AssertCursorLeftTopIs(continuationPrefixLength + 0, 1)),
                 _.Underbar, CheckThat(() => AssertCursorLeftTopIs(continuationPrefixLength + 0, 1))
             ));
         }
 
-        [Fact]
+        [SkippableFact]
         public void ViMoveToEndOfLine_NoOp_OnEmptyLine()
         {
             TestSetup(KeyMode.Vi);
@@ -103,7 +103,7 @@ public void ViMoveToEndOfLine_NoOp_OnEmptyLine()
             const string buffer = "\"\n\n\"";
 
             Test(buffer, Keys(
-                _.DQuote, _.Enter, _.Enter, _.DQuote, _.Escape, _.K,
+                _.DQuote, _.Enter, _.Enter, _.DQuote, _.Escape, _.k,
                 CheckThat(() => AssertCursorLeftTopIs(continuationPrefixLength + 0, 1)),
                 _.Dollar, CheckThat(() => AssertCursorLeftTopIs(continuationPrefixLength + 0, 1))
             ));