[Tests] Add .knm stub consistency test

The test compares stub trees built from .knm files directly and from
the decompiled text. Test data for .class decompiler is reused,
JVM-specific cases are ignored

KT-61354

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/AnnotatedFlexibleTypes/AnnotatedFlexibleTypes.kt

@@ -1,3 +1,6 @@
+// KNM_K2_IGNORE
+// KNM_FE10_IGNORE
+
 package test
 
 public class AnnotatedFlexibleTypes(val javaClass: d.JavaClass) {

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/Annotations/Annotations.kt

@@ -1,3 +1,7 @@
+// Issue: KTIJ-26788 (need stdlib for lazy)
+// KNM_K2_IGNORE
+// KNM_FE10_IGNORE
+
 @a public class Annotations private @a constructor(private @property:a @param:a val c1: Int, @property:a @param:a val c2: Int) {
     @a() val hasValueArguments = 42
 

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/AnnotationsOnNullableTypes/AnnotationsOnNullableTypes.kt

@@ -1,3 +1,5 @@
+// Issue: KTIJ-26761
+// KNM_K2_IGNORE
 public class AnnotationsOnNullableTypes {
     fun B<@A C?>.receiverArgument() {}
 

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/ContextReceiversOnFunctionType/ContextReceiversOnFunctionType.kt

@@ -1,7 +1,7 @@
 // FIR_IDENTICAL
 // JVM_FILE_NAME: ContextReceiversOnFunctionTypeKt
 // !LANGUAGE: +ContextReceivers
-
+// KNM_K2_IGNORE
 fun f(g: context(A, B) Int.(Int) -> Int) {}
 
 class A {

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/LocalClass/LocalClass.kt

@@ -1,4 +1,7 @@
 // FIR_IDENTICAL
+// KNM_K2_IGNORE
+// KNM_FE10_IGNORE
+
 package test
 
 class LocalClass {

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/Modifiers/Modifiers.kt

@@ -1,3 +1,7 @@
+// Issue: KTIJ-26788 (need stdlib for Continuation)
+// KNM_K2_IGNORE
+// KNM_FE10_IGNORE
+
 package test
 import kotlin.coroutines.*
 

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/TopLevelMembersKt/TopLevelMembers.kt

@@ -1,3 +1,6 @@
+// Issue: KTIJ-26761
+// KNM_K2_IGNORE
+
 package foo.TopLevelMembers
 
 fun funWithBlockBody() {

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractDecompiledClassTest.kt

@@ -144,9 +144,7 @@ internal data class TestData(
     companion object {
         fun createFromDirectory(directory: Path): TestData {
             val allFiles = Files.list(directory).collect(Collectors.toList())
-            val mainKotlinFile = allFiles.single { path: Path ->
-                path.name.replaceFirstChar { Character.toUpperCase(it) } == "${directory.name.removeSuffix("Kt")}.kt"
-            }
+            val mainKotlinFile = findMainTestKotlinFile(directory)
             val fileText = mainKotlinFile.readText()
             val jvmFileName = InTextDirectivesUtils.findStringWithPrefixes(fileText, "JVM_FILE_NAME:") ?: directory.name
             val additionalCompilerOptions = InTextDirectivesUtils.findListWithPrefixes(fileText, "// !LANGUAGE: ").map { "-XXLanguage:$it" }
@@ -179,3 +177,9 @@ internal data class TestData(
     }
 }
 
+fun findMainTestKotlinFile(directory: Path): Path {
+    val allFiles = Files.list(directory).collect(Collectors.toList())
+    return allFiles.singleOrNull { path: Path ->
+        path.name.replaceFirstChar { Character.toUpperCase(it) } == "${directory.name.removeSuffix("Kt")}.kt"
+    } ?: error("Test directory should contain a single primary kt source file")
+}

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractStubBuilderTest.kt

@@ -10,6 +10,7 @@ import com.intellij.psi.PsiElement
 import com.intellij.psi.impl.DebugUtil
 import com.intellij.psi.stubs.PsiFileStub
 import com.intellij.psi.stubs.StubElement
+import org.jetbrains.annotations.TestOnly
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.psi.stubs.impl.STUB_TO_STRING_PREFIX
 import org.jetbrains.kotlin.test.KotlinTestUtils
@@ -40,7 +41,8 @@ abstract class AbstractStubBuilderTest : AbstractDecompiledClassTest() {
     protected abstract fun getStubToTest(classFile: VirtualFile): PsiFileStub<*>
 }
 
-private fun StubElement<out PsiElement>.serializeToString(): String {
+@TestOnly
+fun StubElement<out PsiElement>.serializeToString(): String {
     return serializeStubToString(this)
 }