Increase deprecation level for previously deprecated API

- unsupported common exceptions
- common 'synchronized'
- jquery API
- experimental kotlin.time API
- js Math object
- DefaultAsserter constructor-like fun

libraries/kotlin.test/common/src/main/kotlin/kotlin/test/DefaultAsserter.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * 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.
  */
 
@@ -22,8 +22,11 @@ object DefaultAsserter : Asserter {
     }
 }
 
-@Deprecated("DefaultAsserter is an object now, constructor call is not required anymore",
-        ReplaceWith("DefaultAsserter", "kotlin.test.DefaultAsserter"))
+@Deprecated(
+    "DefaultAsserter is an object now, constructor call is not required anymore",
+    ReplaceWith("DefaultAsserter", "kotlin.test.DefaultAsserter"),
+    DeprecationLevel.ERROR
+)
 @kotlin.js.JsName("DefaultAsserterConstructor")
 @Suppress("FunctionName")
 fun DefaultAsserter(): DefaultAsserter = DefaultAsserter