[IR][tests] New test: non-abstract callable member in abstract class becomes abstract

^KT-53663

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/lib1/l1.kt.0

@@ -0,0 +1,6 @@
+package lib1
+
+interface A {
+    fun foo(): Int = 42
+    fun bar(): Int = 42
+}

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/lib1/l1.kt.1

@@ -0,0 +1,6 @@
+package lib1
+
+interface A {
+    fun foo(): Int
+    fun bar(): Int
+}

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/lib1/module.info

@@ -0,0 +1,12 @@
+STEP 0:
+    dependencies: stdlib
+    modifications:
+        U : l1.kt.0 -> l1.kt
+STEP 1:
+    dependencies: stdlib
+    modifications:
+        U : l1.kt.1 -> l1.kt
+STEP 2:
+    dependencies: stdlib
+    modifications:
+        U : l1.kt.0 -> l1.kt

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/lib2/l2.kt

@@ -0,0 +1,15 @@
+package lib2
+
+import lib1.A
+
+class B : A {
+    override fun bar() = -42
+
+    val unlinkedFunctionUsage get() = foo()
+}
+
+class B1 : A {
+    override fun bar() = -42
+
+    val unlinkedFunctionUsage = foo() // Expected failure on class instance initialization.
+}

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/lib2/module.info

@@ -0,0 +1,2 @@
+STEP 0:
+    dependencies: stdlib, lib1

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/main/m.kt

@@ -0,0 +1,60 @@
+import lib1.A
+import lib2.B
+import lib2.B1
+
+fun test1(): String {
+    val a: A = B()
+    return try {
+        val answer: Int = a.foo() // <-- should throw linkage error here
+        println(answer)
+        "FAIL1"
+    } catch(e: Throwable) {
+        e.checkLinkageError("foo", "B")
+    }
+}
+
+fun test2(): String {
+    val a: A = B()
+    val bar = a.bar()
+    return if (bar == -42) "OK" else "bar=$bar"
+}
+
+fun test3(): String {
+    val b = B()
+    return try {
+        val answer: Int = b.unlinkedFunctionUsage // <-- should throw linkage error here
+        println(answer)
+        "FAIL2"
+    } catch (e: Throwable) {
+        e.checkLinkageError("foo", "B")
+    }
+}
+
+fun test4(): String {
+    return try {
+        B1()
+        "FAIL3"
+    } catch (e: Throwable) {
+        e.checkLinkageError("foo", "B1")
+    }
+}
+
+fun box(): String = checkResults(test1(), test2(), test3(), test4())
+
+private fun Throwable.checkLinkageError(symbolName: String, className: String): String {
+    if (this::class.simpleName != "IrLinkageError") return "Unexpected throwable: ${this::class}"
+
+    val expectedMessage = "Abstract function $symbolName is not implemented in non-abstract class $className"
+    val actualMessage = message.orEmpty()
+
+    return if (expectedMessage == actualMessage)
+        "OK"
+    else
+        "EXPECTED: $expectedMessage, ACTUAL: $actualMessage"
+}
+
+private fun checkResults(vararg results: String): String = when {
+    results.isEmpty() -> "no results to check"
+    results.all { it == "OK" } -> "OK"
+    else -> results.joinToString("\n")
+}

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/main/module.info

@@ -0,0 +1,2 @@
+STEP 0:
+    dependencies: stdlib, lib1, lib2

compiler/testData/klibABI/nonAbstractFunctionInInterfaceBecomesAbstract/project.info

@@ -0,0 +1,7 @@
+MODULES: lib1, lib2, main
+
+STEP 0:
+    libs: lib1, lib2, main
+
+STEP 1:
+    libs: lib1