Improve heuristic for filtering synthetic enum methods out

It's not possible to check the exact method signature, as it is
unavailable in dumb stubs for Kotlin's light classes. Yet, it's still
possible to check more things, such as parameter count and access flags.

compiler/resolution.common.jvm/src/org/jetbrains/kotlin/asJava/SyntheticElementUtils.kt

@@ -6,10 +6,22 @@
 package org.jetbrains.kotlin.asJava
 
 import com.intellij.psi.PsiMethod
+import com.intellij.psi.PsiModifier
 import com.intellij.psi.SyntheticElement
-import org.jetbrains.kotlin.builtins.StandardNames
 
 fun isSyntheticValuesOrValueOfMethod(method: PsiMethod): Boolean {
-    if (method !is SyntheticElement) return false
-    return StandardNames.ENUM_VALUE_OF.asString() == method.name || StandardNames.ENUM_VALUES.asString() == method.name
-}
+    if (method is SyntheticElement) {
+        val name = method.name
+        if (name == "values" || name == "valueOf") {
+            if (method.hasModifierProperty(PsiModifier.PUBLIC) && method.hasModifierProperty(PsiModifier.STATIC)) {
+                val parameterCount = method.parameterList.parametersCount
+                when (name) {
+                    "values" -> if (parameterCount == 0) return true
+                    "valueOf" -> if (parameterCount == 1) return true
+                }
+            }
+        }
+    }
+
+    return false
+}