Fix s:ExprCol() sometimes go into infinity loop when calculating indent

Author: shirohana

indent/javascript.vim

@@ -204,7 +204,7 @@ function s:ExprCol()
     return 1
   endif
   let bal = 0
-  while s:SearchLoop('[{}?:]','bW',s:skip_expr)
+  while s:SearchLoop('[{}?:]','bW',s:skip_expr) && bal >= -1
     if s:LookingAt() == ':'
       let bal -= !search('\m:\%#','bW')
     elseif s:LookingAt() == '?'