`%f18` was originally introduced to represent the old Flang driver,
`f18`. With the introduction of the new driver, `flang-new`, we have
been switching to `%flang` (compiler driver) and `%flang_fc1` (frontend
driver) as more generic alternatives.
As most tests have been portend to use the new LIT variables instead of
`%f18`, this is good time to remove it from lit.cfg.py. There's only one
test left that requires the old driver to run. It's updated with:
```
! REQUIRES: old-flang-driver
```
This way we preserve its semantics while reducing the number of
variables in LIT configuration.
Differential Revision: https://reviews.llvm.org/D101281
Until now we've been maintaining 2 test directories for Flang's drivers:
* test/Driver for `f18` (the current driver)
* test/Flang-Driver for `flang-new` (the new driver)
As we have started sharing tests between the drivers, this separation is
no longer required. This patch merges the two test directories. As
suggested in the review, moving forward we'll avoid having tests
specifically for the old driver.
A few notable changes:
* Driver/version-test.f90 and Driver/no-files.f90 are deleted. The
versions for the new driver are more robust, but tricky to share.
* Driver/write-module.f90 is deleted in favour of
Flang-Driver/write-module.f90 (see https://reviews.llvm.org/D97197
for more context)
Differential Revision: https://reviews.llvm.org/D98257