Fix completion tests after "cast required" color change (KT-18089)

#KT-18089 Fixed

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/LookupElementFactory.kt

@@ -77,6 +77,8 @@ class LookupElementFactory(
             val parameter = descriptor.original.valueParameters.singleOrNull() ?: return false
             return parameter.type.isFunctionType
         }
+
+        val CAST_REQUIRED_COLOR = JBColor(0x4E4040, 0x969696)
     }
 
     val insertHandlerProvider = basicFactory.insertHandlerProvider
@@ -272,8 +274,6 @@ class LookupElementFactory(
         return element
     }
 
-    private val castRequiredColor = JBColor(0x4E4040, 0x969696)
-
     private fun LookupElement.boldIfImmediate(weight: CallableWeight?): LookupElement {
         val style = when (weight?.enum) {
             CallableWeightEnum.thisClassMember, CallableWeightEnum.thisTypeExtension -> Style.BOLD
@@ -288,7 +288,7 @@ class LookupElementFactory(
                         presentation.isItemTextBold = true
                     }
                     else {
-                        presentation.itemTextForeground = castRequiredColor
+                        presentation.itemTextForeground = CAST_REQUIRED_COLOR
                         // gray all tail fragments too:
                         val fragments = presentation.tailFragments
                         presentation.clearTail()

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/ExpectedCompletionUtils.kt

@@ -24,9 +24,9 @@ import com.google.gson.JsonParser
 import com.intellij.codeInsight.completion.CompletionType
 import com.intellij.codeInsight.lookup.LookupElement
 import com.intellij.codeInsight.lookup.LookupElementPresentation
-import com.intellij.codeInsight.lookup.impl.LookupCellRenderer
 import com.intellij.ui.JBColor
 import com.intellij.util.ArrayUtil
+import org.jetbrains.kotlin.idea.completion.LookupElementFactory
 import org.jetbrains.kotlin.idea.core.completion.DeclarationLookupObject
 import org.jetbrains.kotlin.idea.test.AstAccessControl
 import org.jetbrains.kotlin.idea.util.module
@@ -346,7 +346,7 @@ object ExpectedCompletionUtils {
             }
             val foreground = presentation.itemTextForeground
             if (foreground != JBColor.foreground()) {
-                assert(foreground == LookupCellRenderer.getGrayedForeground(false))
+                assert(foreground == LookupElementFactory.CAST_REQUIRED_COLOR)
                 if (length > 0) append(" ")
                 append("grayed")
             }