build: Fix benchmark unit from seconds to milliseconds

microtime returns microsecond-precision floats, in seconds, which
multiplied by 1000 is milliseconds. Correct the unit accordingly.

Also while at it, in avoidance of doubt, report the results based
on observed outcome rather than expected outcome.

Change-Id: I6312b132fed44ab5c98500b3e0ce0173e7ddd6f3

scripts/bench.php

@@ -9,8 +9,8 @@
 
 $t = microtime( true );
 CommonPasswords::getFilter();
-$t = ( microtime( true ) - $t ) * 1000;
-echo "Load bloom filter: {$t}s\n";
+$t = round( microtime( true ) - $t, 6 ) * 1000;
+echo "Load bloom filter: {$t}ms\n";
 
 $passwords = [
  'password' => true,
@@ -20,10 +20,10 @@
 foreach ( $passwords as $p => $v ) {
  $t = microtime( true );
  $isCommon = CommonPasswords::isCommon( $p );
- $t = ( microtime( true ) - $t ) * 1000;
- if ( $v ) {
- echo "Time to check a password that is in the filter: {$t}s\n";
+ $t = round( microtime( true ) - $t, 6 ) * 1000;
+ if ( $isCommon ) {
+ echo "Time to check a password that is in the filter: {$t}ms\n";
  } else {
- echo "Time to check a password that is not in the filter: {$t}s\n";
+ echo "Time to check a password that is not in the filter: {$t}ms\n";
  }
 }