Update client.go to allow the use of paths with the heimdall url (#1126)

* Update client.go to allow the use of paths with the heimdall url

As reported to the polygon team 2 months ago in the Ankr polygon slack, the current code prevents the use of a path with the heimdall url, this was fixed in erigon erigontech/erigon@a3a6170 in response to my request by Mark Holt, and it seems this code was just copied from bor where it is incorrect too. This patch fixes that.

* Add reference to path library

* Fix reversed order of values in unit tests and test removal of setting u.path to rawPath (otherwise why do we need rawPath at all) seems like there were work arounds done here in bioth the unit tests AND the makeURL but logic needs to be examined

consensus/bor/heimdall/client.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"path"
 	"sort"
 	"time"
 
@@ -420,7 +421,7 @@ func makeURL(urlString, rawPath, rawQuery string) (*url.URL, error) {
 		return nil, err
 	}
 
-	u.Path = rawPath
+	u.Path = path.Join(u.Path, rawPath)
 	u.RawQuery = rawQuery
 
 	return u, err

consensus/bor/heimdall/client_test.go

@@ -399,7 +399,7 @@ func TestSpanURL(t *testing.T) {
 	const expected = "http://bor0/bor/span/1"
 
 	if url.String() != expected {
-		t.Fatalf("expected URL %q, got %q", url.String(), expected)
+		t.Fatalf("expected URL %q, got %q", expected, url.String())
 	}
 }
 
@@ -414,6 +414,6 @@ func TestStateSyncURL(t *testing.T) {
 	const expected = "http://bor0/clerk/event-record/list?from-id=10&to-time=100&limit=50"
 
 	if url.String() != expected {
-		t.Fatalf("expected URL %q, got %q", url.String(), expected)
+		t.Fatalf("expected URL %q, got %q", expected, url.String())
 	}
 }