Psi2ir: improve exception stack traces

- Do not wrap exceptions resulting from generating error expressions
  multiple times, as that could lead to stack traces where the identical
  code is wrapped many times and is printed in the exception message on
  each step, which was difficult to read
- Add element location (file name, line number & position) to the
  message, similarly to exceptions from codegen, when catching and
  rethrowing exceptions at the top level

compiler/backend-common/src/org/jetbrains/kotlin/backend/common/BackendException.kt

@@ -0,0 +1,8 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common
+
+class BackendException(message: String, cause: Throwable?) : IllegalStateException(message, cause)

compiler/backend-common/src/org/jetbrains/kotlin/backend/common/CodegenUtil.kt

@@ -232,12 +232,13 @@ object CodegenUtil {
     }
 
     @JvmStatic
-    fun reportBackendException(exception: Throwable, phase: String, fileUrl: String?): Nothing {
+    fun reportBackendException(exception: Throwable, phase: String, location: String?, additionalMessage: String? = null): Nothing {
         // CompilationException (the only KotlinExceptionWithAttachments possible here) is already supposed
         // to have all information about the context.
         if (exception is KotlinExceptionWithAttachments) throw exception
-        throw IllegalStateException(
-            getExceptionMessage("Backend", "Exception during $phase", exception, fileUrl),
+        throw BackendException(
+            getExceptionMessage("Backend", "Exception during $phase", exception, location) +
+                    additionalMessage?.let { "\n" + it }.orEmpty(),
             exception
         )
     }