Refactor KotlinJvmBinaryClass, VirtualFileKotlinClass, etc.

VirtualFileKotlinClass now reads its header and name on creation. This is not
lazy enough and may be slower in some circumstances, but has the following
advantage: if anything is wrong in the header, a VirtualFileKotlinClass
instance will not be created at all, making it nearly impossible for the client
code to operate on invalid data causing all kinds of exceptions

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/lazy/resolvers.kt

@@ -75,8 +75,8 @@ fun LazyJavaResolverContext.findClassInJava(fqName: FqName): JavaClassLookupResu
     }
 
     val kotlinClass = kotlinClassFinder.findKotlinClass(fqName)
-    val header = kotlinClass?.getClassHeader()
-    if (kotlinClass != null && header != null) {
+    if (kotlinClass != null) {
+        val header = kotlinClass.getClassHeader()
         if (header.kind == KotlinClassHeader.Kind.CLASS) {
             val descriptor = packageFragmentProvider.resolveKotlinBinaryClass(kotlinClass)
             if (descriptor != null) {

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/kotlin/DeserializedDescriptorResolver.java

@@ -117,8 +117,6 @@ public final class DeserializedDescriptorResolver {
     @Nullable
     private String[] readData(@NotNull KotlinJvmBinaryClass kotlinClass, @NotNull KotlinClassHeader.Kind expectedKind) {
         KotlinClassHeader header = kotlinClass.getClassHeader();
-        if (header == null) return null;
-
         if (header.getKind() == KotlinClassHeader.Kind.INCOMPATIBLE_ABI_VERSION) {
             errorReporter.reportIncompatibleAbiVersion(kotlinClass, header.getVersion());
         }

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/kotlin/KotlinJvmBinaryClass.java

@@ -30,7 +30,7 @@ public interface KotlinJvmBinaryClass {
 
     void visitMembers(@NotNull MemberVisitor visitor);
 
-    @Nullable
+    @NotNull
     KotlinClassHeader getClassHeader();
 
     interface MemberVisitor {

core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/kotlin/header/ReadKotlinClassHeaderAnnotationVisitor.java

@@ -20,7 +20,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.resolve.java.AbiVersionUtil;
 import org.jetbrains.jet.lang.resolve.java.JvmClassName;
-import org.jetbrains.jet.lang.resolve.kotlin.KotlinJvmBinaryClass;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.name.Name;
 
@@ -53,16 +52,6 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
     private KotlinClassHeader.Kind headerKind = null;
     private KotlinSyntheticClass.Kind syntheticClassKind = null;
 
-    private ReadKotlinClassHeaderAnnotationVisitor() {
-    }
-
-    @Nullable
-    public static KotlinClassHeader read(@NotNull KotlinJvmBinaryClass kotlinClass) {
-        ReadKotlinClassHeaderAnnotationVisitor visitor = new ReadKotlinClassHeaderAnnotationVisitor();
-        kotlinClass.loadClassAnnotations(visitor);
-        return visitor.createHeader();
-    }
-
     @Nullable
     public KotlinClassHeader createHeader() {
         if (headerKind == null) {