8349705: java.net.URI.scanIPv4Address throws unnecessary URISyntaxException

Backport-of: a90f323d05f1c90767823b8729b124de0bead265

Author: Xiaolong Peng

src/java.base/share/classes/java/net/URI.java

@@ -3479,7 +3479,7 @@ private int scanIPv4Address(int start, int n, boolean strict)
                 if (q < m) break;
                 return q;
             }
-            fail("Malformed IPv4 address", q);
+            if (strict) fail("Malformed IPv4 address", q);
             return -1;
         }
 
@@ -3508,12 +3508,16 @@ private int parseIPv4Address(int start, int n) {
                 return -1;
             }
 
+            if (p == -1) {
+                return p;
+            }
+
             if (p > start && p < n) {
                 // IPv4 address is followed by something - check that
                 // it's a ":" as this is the only valid character to
                 // follow an address.
                 if (input.charAt(p) != ':') {
-                    p = -1;
+                    return -1;
                 }
             }