[BUGFIX] Create required directories in test bootstrap

When running the core unit tests without setting up TYPO3
using the normal installation procedure then the uploads,
typo3temp, and typo3conf/ext directories do not exist.

Resolves: #59977
Releases: 6.3,6.2
Change-Id: Ib6b8ecd480b83cf818f54d865a4ff61fe62d2893
Reviewed-on: https://review.typo3.org/31216
Reviewed-by: Oliver Klee
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn