Restrict ttls to valid RFC8941 sf-decimal values

bin/varnishtest/tests/r01499.vtc

@@ -10,7 +10,7 @@ server s1 {
 
 varnish v1 -vcl+backend {
 	sub vcl_backend_response {
-		set beresp.ttl = 0.0001s;
+		set beresp.ttl = 0.001s;
 		set beresp.grace = 0s;
 		set beresp.keep = 2s;
 	}

bin/varnishtest/tests/r01879.vtc

@@ -17,7 +17,7 @@ varnish v1 -vcl+backend {
 	import std;
 
 	sub vcl_backend_response {
-		set beresp.ttl = 0.00001s;
+		set beresp.ttl = 0.001s;
 		set beresp.grace = 0.1s;
 		set beresp.keep = 9999s;
 	}

bin/varnishtest/tests/r02319.vtc

@@ -8,7 +8,7 @@ server s1 {
 
 varnish v1 -vcl+backend {
 	sub vcl_backend_fetch {
-		set bereq.between_bytes_timeout = 0.0001s;
+		set bereq.between_bytes_timeout = 0.001s;
 	}
 	sub vcl_backend_response {
 		set beresp.do_stream = false;

bin/varnishtest/tests/r02763.vtc

@@ -29,7 +29,7 @@ varnish v1 -vcl+backend {
 		if (bereq.http.HFM) {
 			set beresp.uncacheable = true;
 		} else {
-			set beresp.ttl = 0.0001s;
+			set beresp.ttl = 0.001s;
 			set beresp.grace = 0s;
 			set beresp.keep = 1m;
 		}

bin/varnishtest/tests/r02946.vtc

@@ -12,7 +12,7 @@ varnish v1 -vcl {
 			return (deliver);
 		}
 		set beresp.status = 200;
-		set beresp.ttl = 0.0001s;
+		set beresp.ttl = 0.001s;
 		set beresp.grace = 1h;
 		return (deliver);
 	}