[Klib] Split up IR header tables onto three parts

There was one monolith protobuf at irHeader.knd, it was
split up onto 4 parts due to performance issues:
  - a small irHeader with some basic info about a module
  - symbols table
  - types table
  - strings table
These 3 tables are then mmapped and accessed by index.

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsIrLinker.kt

@@ -36,6 +36,15 @@ class JsIrLinker(
     override val ModuleDescriptor.irHeader: ByteArray?
         get() = this.kotlinLibrary.irHeader
 
+    override fun readSymbol(moduleDescriptor: ModuleDescriptor, symbolIndex: Int) =
+        moduleDescriptor.kotlinLibrary.symbol(symbolIndex)
+
+    override fun readType(moduleDescriptor: ModuleDescriptor, typeIndex: Int) =
+        moduleDescriptor.kotlinLibrary.type(typeIndex)
+
+    override fun readString(moduleDescriptor: ModuleDescriptor, stringIndex: Int) =
+        moduleDescriptor.kotlinLibrary.string(stringIndex)
+
     override fun declareForwardDeclarations() {
         // since for `knownBuiltIns` such as FunctionN it is possible to have unbound symbols after deserialization
         // reference them through out lazy symbol table
@@ -48,5 +57,4 @@ class JsIrLinker(
             ArrayList(unboundTypeParameters).forEach { lazyWrapper.referenceTypeParameter(it.descriptor) }
         }
     }
-}
-
+}