[FIR] Automatically generated abstract classes instead of interfaces if possible

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/declarations/FirJavaField.kt

@@ -8,9 +8,6 @@ package org.jetbrains.kotlin.fir.java.declarations
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibility
-import org.jetbrains.kotlin.fir.FirAnnotationContainer
-import org.jetbrains.kotlin.fir.FirElement
-import org.jetbrains.kotlin.fir.FirPureAbstractElement
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.impl.FirDeclarationStatusImpl
@@ -37,7 +34,7 @@ class FirJavaField(
     override var returnTypeRef: FirTypeRef,
     override val isVar: Boolean,
     isStatic: Boolean
-) : FirPureAbstractElement(), FirAbstractAnnotatedElement, FirField {
+) : FirAbstractAnnotatedElement, FirField() {
     init {
         symbol.bind(this)
     }