Add mode to run kapt with JVM IR, use in tests

Currently JVM IR is not supported in kapt, so almost all tests are
failing, and thus are muted with IGNORE_BACKEND.

 #KT-49682

plugins/kapt3/kapt3-compiler/testData/converter/javaKeywords.kt

@@ -1,4 +1,4 @@
 class default {
     lateinit val extends: String
     fun implements(instanceof: Int) {}
-}
+}