[Wasm] Remove unnecessary testHelpers and add assertions from stdlib

libraries/stdlib/wasm/src/kotlin/Assertions.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2021 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 kotlin
+
+// TODO: Make this dependant on the compiler flag (like -ea on JVM)
+
+/**
+ * Throws an [AssertionError] if the [value] is false.
+ */
+@kotlin.internal.InlineOnly
+public inline fun assert(value: Boolean) {
+    assert(value) { "Assertion failed" }
+}
+
+/**
+ * Throws an [AssertionError] calculated by [lazyMessage] if the [value] is false.
+ */
+@kotlin.internal.InlineOnly
+public inline fun assert(value: Boolean, lazyMessage: () -> Any) {
+    if (!value) {
+        val message = lazyMessage()
+        throw AssertionError(message)
+    }
+}