Rename platform to header.

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/descriptors/JavaPropertyDescriptor.java

@@ -46,7 +46,7 @@ public class JavaPropertyDescriptor extends PropertyDescriptorImpl implements Ja
             boolean isStaticFinal
     ) {
         super(containingDeclaration, original, annotations, modality, visibility, isVar, name, kind, source,
-              /* lateInit = */ false, /* isConst = */ false, /* isPlatform = */ false, /* isImpl = */ false, /* isExternal = */ false);
+              /* lateInit = */ false, /* isConst = */ false, /* isHeader = */ false, /* isImpl = */ false, /* isExternal = */ false);
 
         this.isStaticFinal = isStaticFinal;
     }

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaClassDescriptor.kt

@@ -100,7 +100,7 @@ class LazyJavaClassDescriptor(
     override fun isInner() = isInner
     override fun isData() = false
     override fun isCompanionObject() = false
-    override fun isPlatform() = false
+    override fun isHeader() = false
     override fun isImpl() = false
 
     private val typeConstructor = c.storageManager.createLazyValue { LazyJavaClassTypeConstructor() }