test-paths: fix up json output to match $TESTTMP on Windows

Without this, the paths were in the form "C:\\Users\\Matt\\AppData...".  The
test runner wouldn't collapse it down to $TESTTMP, which uses single
backslashes.

tests/test-paths.t

@@ -59,24 +59,24 b' with paths:'
 formatter output with paths:
 
   $ echo 'dupe:pushurl = https://example.com/dupe' >> .hg/hgrc
-  $ hg paths -Tjson
+  $ hg paths -Tjson | sed 's|\\\\|\\|g'
   [
    {
     "name": "dupe",
     "pushurl": "https://example.com/dupe",
-    "url": "$TESTTMP/b#tip"
+    "url": "$TESTTMP/b#tip" (glob)
    },
    {
     "name": "expand",
-    "url": "$TESTTMP/a/$SOMETHING/bar"
+    "url": "$TESTTMP/a/$SOMETHING/bar" (glob)
    }
   ]
-  $ hg paths -Tjson dupe
+  $ hg paths -Tjson dupe | sed 's|\\\\|\\|g'
   [
    {
     "name": "dupe",
     "pushurl": "https://example.com/dupe",
-    "url": "$TESTTMP/b#tip"
+    "url": "$TESTTMP/b#tip" (glob)
    }
   ]
   $ hg paths -Tjson -q unknown