K2 LL API: implement automatic diagnostic suppression

compiler/frontend.common/src/org/jetbrains/kotlin/diagnostics/DiagnosticReporter.kt

@@ -27,6 +27,9 @@ abstract class MutableDiagnosticContext : DiagnosticContext {
 
 abstract class DiagnosticReporter {
     abstract fun report(diagnostic: KtDiagnostic?, context: DiagnosticContext)
+
+    open fun checkAndCommitReportsOn(element: AbstractKtSourceElement, context: DiagnosticContext?) {
+    }
 }
 
 open class KtDiagnosticReporterWithContext(

compiler/frontend.common/src/org/jetbrains/kotlin/diagnostics/impl/PendingDiagnosticsCollectorWithSuppress.kt

@@ -29,11 +29,11 @@ class PendingDiagnosticsCollectorWithSuppress : BaseDiagnosticsCollector() {
         }
     }
 
-    fun checkAndCommitReportsOn(
+    override fun checkAndCommitReportsOn(
         element: AbstractKtSourceElement,
-        context: DiagnosticContext?,
-        commitEverything: Boolean
+        context: DiagnosticContext?
     ) {
+        val commitEverything = context == null
         for ((path, pendingList) in pendingDiagnosticsByFilePath) {
             val committedList = _diagnosticsByFilePath.getOrPut(path) { mutableListOf() }
             val iterator = pendingList.iterator()