[FIR] Part 2. Setup running platform checkers in tests

^KT-58881

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/compiler/based/LLDiagnosticParameterChecker.kt

@@ -22,7 +22,8 @@ import org.jetbrains.kotlin.utils.exceptions.withPsiEntry
 internal class LLDiagnosticParameterChecker(testServices: TestServices) : FirAnalysisHandler(testServices) {
     override fun processModule(module: TestModule, info: FirOutputArtifact) {
         for (part in info.partsForDependsOnModules) {
-            val diagnostics = part.firAnalyzerFacade.runCheckers().values.flatten()
+            val facade = part.firAnalyzerFacade as LowLevelFirAnalyzerFacade
+            val diagnostics = facade.runCheckers().values.flatten()
 
             for (diagnostic in diagnostics) {
                 checkDiagnosticIsSuitableForFirIde(diagnostic as KtPsiDiagnostic)

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/compiler/based/LowLevelFirAnalyzerFacade.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.analysis.low.level.api.fir.api.LLFirResolveSession
 import org.jetbrains.kotlin.analysis.low.level.api.fir.api.collectDiagnosticsForFile
 import org.jetbrains.kotlin.diagnostics.KtDiagnostic
 import org.jetbrains.kotlin.fir.AbstractFirAnalyzerFacade
+import org.jetbrains.kotlin.fir.analysis.checkers.MppCheckerKind
 import org.jetbrains.kotlin.fir.declarations.FirFile
 import org.jetbrains.kotlin.fir.pipeline.FirResult
 import org.jetbrains.kotlin.fir.pipeline.ModuleCompilerAnalyzedOutput
@@ -34,7 +35,8 @@ open class LowLevelFirAnalyzerFacade(
 
     private var resolved: Boolean = false
 
-    override fun runCheckers(): Map<FirFile, List<KtDiagnostic>> {
+    // TODO: investigate
+    fun runCheckers(): Map<FirFile, List<KtDiagnostic>> {
         if (!resolved) {
             runResolution()
             resolved = true