JVM: do not write trivial SMAPs to classes outside inline funs

where trivial == those that map the file to itself.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ClassCodegen.kt

@@ -89,8 +89,6 @@ abstract class ClassCodegen protected constructor(
         )
     }
 
-    internal var writeSourceMap: Boolean = withinInline
-
     private var regeneratedObjectNameGenerators = mutableMapOf<String, NameGenerator>()
 
     fun getRegeneratedObjectNameGenerator(function: IrFunction): NameGenerator {
@@ -145,7 +143,7 @@ abstract class ClassCodegen protected constructor(
 
         generateInnerAndOuterClasses()
 
-        if (writeSourceMap) {
+        if (withinInline || !smap.isTrivial) {
             visitor.visitSMAP(smap, !context.state.languageVersionSettings.supportsFeature(LanguageFeature.CorrectSourceMappingSyntax))
         } else {
             visitor.visitSource(smap.sourceInfo!!.source, null)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/IrSourceCompilerForInline.kt

@@ -86,7 +86,7 @@ class IrSourceCompilerForInline(
         }
 
     override val lazySourceMapper: SourceMapper
-        get() = codegen.smap.also { codegen.classCodegen.writeSourceMap = true }
+        get() = codegen.smap
 
     override fun generateLambdaBody(lambdaInfo: ExpressionLambda): SMAPAndMethodNode =
         FunctionCodegen((lambdaInfo as IrExpressionLambdaImpl).function, codegen.classCodegen, codegen).generate()