Use possible incompatible metadata as a fallback for incremental analysis

If LeverVersion is set to greater than 1 of the current compiler version, metadata became null here org.jetbrains.kotlin.load.kotlin.header.ReadKotlinClassHeaderAnnotationVisitor.createHeader, which leads to NPE during incremental analysis. Using the same incompatible data as fallback prevent it

#KTIJ-20954 Fixed

Merge-request: KT-MR-5680
Merged-by: Aleksei Cherepanov <aleksei.cherepanov@jetbrains.com>

build-common/src/org/jetbrains/kotlin/incremental/IncrementalJvmCache.kt

@@ -652,7 +652,7 @@ class KotlinClassInfo constructor(
             return KotlinClassInfo(
                 classId,
                 classHeader.kind,
-                classHeader.data ?: emptyArray(),
+                classHeader.data ?: classHeader.incompatibleData ?: emptyArray(),
                 classHeader.strings ?: emptyArray(),
                 classHeader.multifileClassName,
                 constantsMap = constantsAndInlineFunctions.first,

jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/build/KotlinJpsBuildTestIncremental.kt

@@ -148,6 +148,27 @@ class KotlinJpsBuildTestIncremental : KotlinJpsBuildTest() {
         languageOrApiVersionChanged(CommonCompilerArguments::apiVersion)
     }
 
+    @WorkingDir("LanguageOrApiVersionChanged")
+    fun testLanguageVersionExperimental() {
+        initProject(LibraryDependency.JVM_MOCK_RUNTIME)
+        val module = myProject.modules.first()
+        val args = module.kotlinCompilerArguments
+
+        // Try to set Language version to Stable+2 (there is no promises that metadata will be supported)
+        val experimentalLevelVersion: LanguageVersion
+        try {
+            experimentalLevelVersion = LanguageVersion.values()[LanguageVersion.LATEST_STABLE.ordinal+2]
+        } catch (e: ArrayIndexOutOfBoundsException) {
+            // there is no Stable+2 version for now, skiping test
+            return
+        }
+        CommonCompilerArguments::languageVersion.set(args, experimentalLevelVersion.versionString)
+        myProject.kotlinCommonCompilerArguments = args
+
+        buildAllModules().assertSuccessful()
+        assertCompiled(KotlinBuilder.KOTLIN_BUILDER_NAME, "src/Bar.kt", "src/Foo.kt")
+    }
+
     private fun languageOrApiVersionChanged(versionProperty: KMutableProperty1<CommonCompilerArguments, String?>) {
         initProject(LibraryDependency.JVM_MOCK_RUNTIME)