HttpsRedirectWebFilter can redirect to `https:/`

[rwinch]

This is quite possibly a bug in the underlying component(s), but the following test will fail:

this.webTestClient
	.get()
	.uri("/")
	.exchange()
	.expectHeader().location("https://localhost/"); // location = "https:/"

[mehrdadbozorgmehr]

If this issue is still not resolved, I can work on it. @rwinch