test-run-tests: accept more levels of precision and trailing ws (issue4440)

simplejson produces slightly different output from the built-in json
module, specifically:
  * It uses 0.000 instead of 0.0000
  * It likes to put a trailing space after a comma

This change works around both of those variations.

tests/test-run-tests.t

@@ -416,22 +416,22 b' test for --json'
   $ cat report.json
   testreport ={
       "test-failure.t": [\{] (re)
-          "csys": "\s*[\d\.]{5}",  (re)
-          "cuser": "\s*[\d\.]{5}",  (re)
-          "result": "failure", 
-          "time": "\s*[\d\.]{5}" (re)
-      }, 
+          "csys": "\s*[\d\.]{4,5}", ? (re)
+          "cuser": "\s*[\d\.]{4,5}", ? (re)
+          "result": "failure", ? (re)
+          "time": "\s*[\d\.]{4,5}" (re)
+      }, ? (re)
       "test-skip.t": {
-          "csys": "\s*[\d\.]{5}",  (re)
-          "cuser": "\s*[\d\.]{5}",  (re)
-          "result": "skip", 
-          "time": "\s*[\d\.]{5}" (re)
-      }, 
+          "csys": "\s*[\d\.]{4,5}", ? (re)
+          "cuser": "\s*[\d\.]{4,5}", ? (re)
+          "result": "skip", ? (re)
+          "time": "\s*[\d\.]{4,5}" (re)
+      }, ? (re)
       "test-success.t": [\{] (re)
-          "csys": "\s*[\d\.]{5}",  (re)
-          "cuser": "\s*[\d\.]{5}",  (re)
-          "result": "success", 
-          "time": "\s*[\d\.]{5}" (re)
+          "csys": "\s*[\d\.]{4,5}", ? (re)
+          "cuser": "\s*[\d\.]{4,5}", ? (re)
+          "result": "success", ? (re)
+          "time": "\s*[\d\.]{4,5}" (re)
       }
   } (no-eol)