fix text parser regex for multiline tags (fix #3526)

Author: yyx990803

src/compiler/parser/text-parser.js

@@ -3,7 +3,7 @@
 import { cached } from 'shared/util'
 import { parseFilters } from './filter-parser'
 
-const defaultTagRE = /\{\{((?:.|\\n)+?)\}\}/g
+const defaultTagRE = /\{\{((?:.|\n)+?)\}\}/g
 const regexEscapeRE = /[-.*+?^${}()|[\]\/\\]/g
 
 const buildRegex = cached(delimiters => {