[IR] Move some inline utils from backend.common into ir.util

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrInlineUtils.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.util
+
+import org.jetbrains.kotlin.ir.declarations.IrDeclaration
+import org.jetbrains.kotlin.ir.declarations.IrFunction
+import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.symbols.IrFileSymbol
+
+val IrInlinedFunctionBlock.inlineDeclaration: IrDeclaration
+    get() = when (val element = inlinedElement) {
+        is IrFunction -> element
+        is IrFunctionExpression -> element.function
+        is IrFunctionReference -> element.symbol.owner
+        is IrPropertyReference -> element.symbol.owner
+        else -> throw AssertionError("Not supported ir element for inlining ${element.dump()}")
+    }
+private val IrInlinedFunctionBlock.inlineFunction: IrFunction?
+    get() = when (val element = inlinedElement) {
+        is IrFunction -> element
+        is IrFunctionExpression -> element.function
+        is IrFunctionReference -> element.symbol.owner.takeIf { it.isInline }
+        else -> null
+    }
+
+fun IrInlinedFunctionBlock.isFunctionInlining(): Boolean {
+    return this.inlinedElement is IrFunction
+}
+
+fun IrInlinedFunctionBlock.isLambdaInlining(): Boolean {
+    return !isFunctionInlining()
+}
+
+val IrContainerExpression.innerInlinedBlockOrThis: IrContainerExpression
+    get() = (this as? IrReturnableBlock)?.statements?.singleOrNull() as? IrInlinedFunctionBlock ?: this
+val IrReturnableBlock.inlineFunction: IrFunction?
+    get() = (this.statements.singleOrNull() as? IrInlinedFunctionBlock)?.inlineFunction
+val IrReturnableBlock.sourceFileSymbol: IrFileSymbol?
+    get() = inlineFunction?.fileOrNull?.symbol