Update NimbleXCTestHandler.swift

access level for record failure, which can be used in custom AssertionHandler class

Sources/Nimble/Adapters/NimbleXCTestHandler.swift

@@ -61,7 +61,7 @@ func isXCTestAvailable() -> Bool {
 #endif
 }
 
-private func recordFailure(_ message: String, location: SourceLocation) {
+public func recordFailure(_ message: String, location: SourceLocation) {
 #if SWIFT_PACKAGE
     XCTFail("\(message)", file: location.file, line: location.line)
 #else