Untie Symbols class from CommonBackendContext

`Symbols.context` property is actually unused. Let's drop
it as it makes harder to create an instance of this class.

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmBackendContext.kt

@@ -112,7 +112,7 @@ class WasmBackendContext(
         PropertyLazyInitialization(enabled = propertyLazyInitialization, eagerInitialization = wasmSymbols.eagerInitialization)
 
     override val ir = object : Ir<WasmBackendContext>(this, irModuleFragment) {
-        override val symbols: Symbols<WasmBackendContext> = wasmSymbols
+        override val symbols: Symbols = wasmSymbols
         override fun shouldGenerateHandlerParameterForDefaultBodyFun() = true
     }
 

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt

@@ -32,9 +32,9 @@ import java.lang.IllegalArgumentException
 
 @OptIn(ObsoleteDescriptorBasedAPI::class)
 class WasmSymbols(
-    context: WasmBackendContext,
+    private val context: WasmBackendContext,
     private val symbolTable: SymbolTable
-) : Symbols<WasmBackendContext>(context, context.irBuiltIns, symbolTable) {
+) : Symbols(context.irBuiltIns, symbolTable) {
 
     private val kotlinTopLevelPackage: PackageViewDescriptor =
         context.module.getPackage(FqName("kotlin"))