[TASK] Remove traces of unsupported platform `Oracle`

Albeit never officially supported some workarounds
has been introduced in several places to support
Oracle at least partly.

It does not make sense to keep traces of special
handling code flows for unsupported dbms vendors
and versions as required adjustments at mandantory
places are not included, for example during the
database analyser step. Beside that, these changes
could not be properly tested any way.

Traces of the unsupported `Oracle` platform are
now removed to cleanup the code base and considered
as non-breaking - due to not officially supported
and applying the same rule as for internal marked
code.

Resolves: #102880
Releases: main
Change-Id: I5ad3c737278644d17d578beb31132c5fbdc246ef
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82526


Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>