8305312: Enhanced path handling

Reviewed-by: yan
Backport-of: cb7cef2b85264c2bd2d00f1c0e5010969aa618d3

Author: martinuy

src/java.base/unix/classes/sun/nio/fs/UnixUriUtils.java

@@ -75,10 +75,6 @@ static Path fromUri(UnixFileSystem fs, URI uri) {
         int pos = 0;
         while (pos < len) {
             char c = p.charAt(pos++);
-            if ((c == '/') && (pos < len) && (p.charAt(pos) == '/')) {
-                // skip redundant slashes
-                continue;
-            }
             byte b;
             if (c == '%') {
                 assert (pos+2) <= len;
@@ -92,6 +88,10 @@ static Path fromUri(UnixFileSystem fs, URI uri) {
                     throw new IllegalArgumentException("Bad escape");
                 b = (byte)c;
             }
+            if (b == '/' && rlen > 0 && result[rlen-1] == '/') {
+                // skip redundant slashes
+                continue;
+            }
             result[rlen++] = b;
         }
         if (rlen != result.length)