Handle \r when reading cache

Caches are read and written in binary mode (no \r even on Windows).
However, depending on git settings cache samples may use it anyway.

Fixes remaining tests for Windows.

Author: mpeterv

src/luacheck/cache.lua

@@ -184,7 +184,9 @@ local function load_cached(cached)
 end
 
 local function check_version_header(fh)
-   return fh:read() == "" and tonumber(fh:read()) == cache.format_version
+   local first_line = fh:read()
+
+   return (first_line == "" or first_line == "\r") and tonumber(fh:read()) == cache.format_version
 end
 
 local function write_version_header(fh)
@@ -217,6 +219,10 @@ function cache.load(cache_filename, filenames, mtimes)
          return result
       end
 
+      if filename:sub(-1) == "\r" then
+         filename = filename:sub(1, -2)
+      end
+
       local mtime = fh:read()
       local cached = fh:read()