Move checkTypePosition to VarianceChecker in frontend

This is a partial revert of 279ff0b, which is no longer needed because
of the previous commit

compiler/tests/org/jetbrains/kotlin/types/AbstractTypeBindingTest.kt

@@ -88,7 +88,7 @@ abstract class AbstractTypeBindingTest : KotlinTestWithEnvironment() {
             if (argument.projection.isStarProjection)
                 printlnWithNoIndent("*")
             else printlnWithNoIndent("${projection}${argument.projection.type.render()}")
-            print(argument.holder)
+            print(argument.binding)
             return this
         }