JS: better error reporting for V8 runner

In case of stack overflow both the code and the memory release
caused an exception. Only the latter was shown, and it did
not contain much useful information.

js/js.tests/test/org/jetbrains/kotlin/js/test/JsTestChecker.kt

@@ -171,11 +171,19 @@ object V8IrJsTestChecker : AbstractJsTestChecker() {
 
         val v8 = ScriptEngineV8()
 
-        return try {
+        val v = try {
             files.forEach { v8.loadFile(it) }
             v8.f()
-        } finally {
-            v8.release()
+        } catch (t: Throwable) {
+            try {
+                v8.release()
+            } finally {
+                // Don't mask the original exception
+                throw t
+            }
         }
+        v8.release()
+
+        return v
     }
 }