CodeCleanup: eliminate unnecessary base class and make the children unvirtual.

CodeCleanup: eliminate unnecessary base class and make the children unvirtual.

I found some strange split in deopt entry points generator.
The code for table entry generator had two classes.
It is safe to join these classes together and drop virtual.

BUG=
LOG=n

Review URL: https://codereview.chromium.org/1010413003

Cr-Commit-Position: refs/heads/master@{#27264}