Get rid of 'class object' usages in code and builtins

Replace some comments and library usages as well

compiler/tests/org/jetbrains/kotlin/jvm/compiler/AbstractSMAPBaseTest.kt

@@ -98,7 +98,7 @@ public trait AbstractSMAPBaseTest {
     }
 
     class SMAPAndFile(val smap: String?, val sourceFile: String) {
-        class object {
+        companion object {
             fun SMAPAndFile(smap: String?, sourceFile: File) = SMAPAndFile(smap, getPath(sourceFile))
 
             public fun getPath(file: File): String {

compiler/tests/org/jetbrains/kotlin/jvm/compiler/MultiModuleJavaAnalysisCustomTest.kt

@@ -165,7 +165,7 @@ public class MultiModuleJavaAnalysisCustomTest : UsefulTestCase() {
         )
     }
 
-    class object {
+    companion object {
         val PATH_TO_TEST_ROOT_DIR = "compiler/testData/multiModule/java/custom"
     }
 }

compiler/tests/org/jetbrains/kotlin/jvm/runtime/AbstractJvmRuntimeDescriptorLoaderTest.kt

@@ -52,7 +52,7 @@ import java.net.URLClassLoader
 import java.util.regex.Pattern
 
 public abstract class AbstractJvmRuntimeDescriptorLoaderTest : TestCaseWithTmpdir() {
-    class object {
+    companion object {
         private val renderer = DescriptorRendererBuilder()
                 .setWithDefinedIn(false)
                 .setExcludedAnnotationClasses(listOf(

compiler/tests/org/jetbrains/kotlin/resolve/constants/evaluate/AbstractEvaluateExpressionTest.kt

@@ -108,7 +108,7 @@ public abstract class AbstractEvaluateExpressionTest : AbstractAnnotationDescrip
         }
     }
 
-    class object {
+    companion object {
         val pattern = Pattern.compile(".+(?=:)")
     }
 }