[IR] Use full name for expect/actual functions linking, simplify code

Don't put type parameters to expect-actual map since it's useless

^KT-56329 Fixed

compiler/testData/codegen/box/multiplatform/multiModule/kt-56329.kt

@@ -0,0 +1,27 @@
+// TARGET_BACKEND: JVM
+// !LANGUAGE: +MultiPlatformProjects
+// ISSUE: KT-56329
+
+// MODULE: common
+// TARGET_PLATFORM: Common
+// FILE: common.kt
+
+expect class S
+
+expect fun <T> foo(y: T): String
+
+expect fun <T> foo(y: T, x: S): String
+
+fun ok() = foo(1) + foo(2, "K" as S)
+
+// MODULE: jvm()()(common)
+// TARGET_PLATFORM: JVM
+// FILE: main.kt
+
+actual typealias S = String
+
+actual fun <T> foo(y: T) = "O"
+
+actual fun <T> foo(y: T, x: S) = x
+
+fun box() = ok()