Minor, use String instead of DeprecationLevel

Using classes from runtime in the compiler is confusing and doesn't allow to
incompatibly change them

core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java

@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.builtins;
 
-import kotlin.DeprecationLevel;
 import kotlin.SetsKt;
 import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
@@ -393,8 +392,8 @@ public abstract class KotlinBuiltIns {
     }
 
     @Nullable
-    public ClassDescriptor getDeprecationLevelEnumEntry(@NotNull DeprecationLevel level) {
-        return getEnumEntry(getDeprecationLevelEnum(), level.name());
+    public ClassDescriptor getDeprecationLevelEnumEntry(@NotNull String level) {
+        return getEnumEntry(getDeprecationLevelEnum(), level);
     }
 
     @NotNull

core/descriptors/src/org/jetbrains/kotlin/descriptors/annotations/annotationUtil.kt

@@ -29,7 +29,7 @@ import org.jetbrains.kotlin.types.Variance
 public fun KotlinBuiltIns.createDeprecatedAnnotation(
         message: String,
         replaceWith: String,
-        level: DeprecationLevel = DeprecationLevel.WARNING
+        level: String = "WARNING"
 ): AnnotationDescriptor {
     val deprecatedAnnotation = deprecatedAnnotation
     val parameters = deprecatedAnnotation.unsubstitutedPrimaryConstructor!!.valueParameters
@@ -52,7 +52,7 @@ public fun KotlinBuiltIns.createDeprecatedAnnotation(
                                     SourceElement.NO_SOURCE
                             )
                     ),
-                    parameters["level"] to EnumValue(getDeprecationLevelEnumEntry(level)!!)
+                    parameters["level"] to EnumValue(getDeprecationLevelEnumEntry(level) ?: error("Deprecation level $level not found"))
             ),
             SourceElement.NO_SOURCE)
 }

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorFactory.java

@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.resolve;
 
-import kotlin.DeprecationLevel;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
@@ -133,11 +132,9 @@ public class DescriptorFactory {
 
     @NotNull
     public static PropertyDescriptor createEnumValuesProperty(@NotNull ClassDescriptor enumClass) {
-        AnnotationsImpl annotations = AnnotationsImpl.createWithNoTarget(
-                AnnotationUtilKt.createDeprecatedAnnotation(getBuiltIns(enumClass),
-                                                            "Use 'values()' function instead", "this.values()",
-                                                            DeprecationLevel.ERROR)
-        );
+        AnnotationsImpl annotations = AnnotationsImpl.createWithNoTarget(AnnotationUtilKt.createDeprecatedAnnotation(
+                getBuiltIns(enumClass), "Use 'values()' function instead", "this.values()", "ERROR"
+        ));
 
         PropertyDescriptorImpl values =
                 PropertyDescriptorImpl.create(