Revert of Extend big-disjunction optimization to case-independent regexps (patchset #5 id:80001 of https://codereview.chromium.org/1182783009/)

Reason for revert:
[Sheriff] Test times out now on msan:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/builds/2947

Original issue's description:
> Extend big-disjunction optimization to case-independent regexps
>
> R=yangguo@chromium.org
> BUG=chromium:482998
> LOG=n
>
> Committed: https://crrev.com/d2135603bcf462e15a1284d8ed969f6692610dda
> Cr-Commit-Position: refs/heads/master@{#29264}

TBR=yangguo@chromium.org,erikcorry@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:482998

Review URL: https://codereview.chromium.org/1204013003

Cr-Commit-Position: refs/heads/master@{#29266}