Add contract for fail

Created another fail method with a non-nullable lambda parameter

Issue: #1866

Author: awelless

Diff for: junit-jupiter-api/src/main/kotlin/org/junit/jupiter/api/Assertions.kt

@@ -29,6 +29,18 @@ import kotlin.contracts.contract
 fun fail(message: String?, throwable: Throwable? = null): Nothing =
     Assertions.fail<Nothing>(message, throwable)
 
+/**
+ * @see Assertions.fail
+ */
+@JvmName("fail_nonNullableLambda")
+fun fail(message: () -> String): Nothing {
+    contract {
+        callsInPlace(message)
+    }
+
+    return Assertions.fail<Nothing>(message)
+}
+
 /**
  * @see Assertions.fail
  */