Fix Blazy Blurry performance issues of not exist derivative image and enhance the logic of the encoding of base64 image

Problem/Motivation

I have 2 issues related to blazy blurry behaviour:

1. The uri for some images is not found, which made a problem for generating the blurry image.
2. There is a problem with the logic of encoding some large files using fopen function

Followup logical error after
#3099787: Fix generate image Uri for blurry from the fallback image style when responsive image style is used

Steps to reproduce

Given that we had a drush image:flush
Then no images under image styles at this time
When we load a page for the first time after the flush of images
And images in the site that using the "Blazy Blurry" option for the media view mode
And we do have a very big originally uploaded with big dimension and file size
Then the blazy blurry image will not load
But when we load the page for the 2nd page
The blazy blurry image for the fallback image style for responsive image style will be present
Then the blazy blurry image will load and show up in the page

Proposed resolution

I suggest generating a new image derivative based on the needed image style to make sure the file exists before creating the new image for blazy blurry style. Also, I think we can improve the encoding way of the image using file_get_contents that may solve the problem with large files.

Remaining tasks

• Patch
• Test round
• Quick fix release

User interface changes

No missing images on the first load of images after a drush image:flush

API changes

None

Data model changes

None