Refactor the test on masks

Author: eGavr

test/differ/fixtures/first/mask.html

@@ -1,4 +1,4 @@
 AZ<meta charset="UTF-32">{{UTF-\d{1,2}}
 <span style="url(blah?rnd={{\d}})">{{UTF-\d\{1,2\}}}
-<div id=".*{{\d\.\d}}.?">
+<div id=".*{{\d\.\d}}?">
 <div id="blah{{\d+}}blah"></div>bl{{\}}{=ah 5

test/differ/fixtures/second/mask.html

@@ -1,5 +1,5 @@
 {{[A-Z]+}}<meta charset="{{UTF-\d{1,2}}}">UTF-1{1,2
 <span style="url(blah?rnd=1)">UTF-1{1,2}
-<div id=".*1.1.?">
+<div id=".*1.1?">
 <div id="blah12345blah"></div>{{bl\{\{\\\}\}{=ah\s\d}}