fix routing issue for esoteric characters in gorilla/mux (#8967)

First step is to ensure that Path component is not decoded
by gorilla/mux to avoid routing issues while handling
certain characters while uploading through PutObject()

Delay the decoding and use PathUnescape() to escape
the `object` path component.

Thanks to @buengese and @ncw for neat test cases for us
to test with.

Fixes #8950
Fixes #8647

cmd/object-api-utils_test.go

@@ -105,13 +105,24 @@ func TestIsValidObjectName(t *testing.T) {
 		{"f*le", true},
 		{"contains-^-carret", true},
 		{"contains-|-pipe", true},
-		{"contains-\"-quote", true},
 		{"contains-`-tick", true},
 		{"..test", true},
 		{".. test", true},
 		{". test", true},
 		{".test", true},
 		{"There are far too many object names, and far too few bucket names!", true},
+		{"!\"#$%&'()*+,-.／:;<=>?@[\\]^_`{|}~/!\"#$%&'()*+,-.／:;<=>?@[\\]^_`{|}~)", true},
+		{"!\"#$%&'()*+,-.／:;<=>?@[\\]^_`{|}~", true},
+		{"␀␁␂␃␄␅␆␇␈␉␊␋␌␍␎␏␐␑␒␓␔␕␖␗␘␙␚␛␜␝␞␟␡", true},
+		{"trailing VT␋/trailing VT␋", true},
+		{"␋leading VT/␋leading VT", true},
+		{"~leading tilde", true},
+		{"\rleading CR", true},
+		{"\nleading LF", true},
+		{"\tleading HT", true},
+		{"trailing CR\r", true},
+		{"trailing LF\n", true},
+		{"trailing HT\t", true},
 		// cases for which test should fail.
 		// passing invalid object names.
 		{"", false},
@@ -122,7 +133,6 @@ func TestIsValidObjectName(t *testing.T) {
 		{" ../etc", false},
 		{"./././", false},
 		{"./etc", false},
-		{`contains-\-backslash`, false},
 		{`contains//double/forwardslash`, false},
 		{`//contains/double-forwardslash-prefix`, false},
 		{string([]byte{0xff, 0xfe, 0xfd}), false},