tests(smoke): use range for unused bytes expectations (#10473)

lighthouse-cli/test/smokehouse/test-definitions/byte-efficiency/expectations.js

@@ -149,22 +149,22 @@ const expectations = [
               },
               {
                 url: 'http://localhost:10200/byte-efficiency/bundle.js',
-                totalBytes: 12913,
-                wastedBytes: 5827,
+                totalBytes: '12913 +/- 1000',
+                wastedBytes: '5827 +/- 200',
                 sources: [
                   '…./b.js',
                   '…./c.js',
                   '…webpack/bootstrap',
                 ],
                 sourceBytes: [
-                  4417,
-                  2200,
-                  2809,
+                  '4417 +/- 50',
+                  '2200 +/- 50',
+                  '2809 +/- 50',
                 ],
                 sourceWastedBytes: [
-                  2191,
-                  2182,
-                  1259,
+                  '2191 +/- 50',
+                  '2182 +/- 50',
+                  '1259 +/- 50',
                 ],
               },
             ],