regression-tests: run tests using bash

[hugolm84]

Convenience script for running regression tests on Linux. Current results on Ubuntu and gcc11:

./run-tests.sh
TRANSPILE:
34 SUCCESS
8 FAILED
./test-results/mixed-lifetime-safety-pointer-init-3.cpp2
./test-results/mixed-initialization-safety-1.cpp2
./test-results/mixed-lifetime-safety-pointer-init-2.cpp2
./test-results/mixed-initialization-safety-2.cpp2
./test-results/mixed-lifetime-safety-pointer-init-1.cpp2
./test-results/pure2-bounds-safety-pointer-arithmetic-error.cpp2
./test-results/pure2-lifetime-safety-pointer-init-1.cpp2
./test-results/pure2-lifetime-safety-reject-null.cpp2
COMPILE:
33 SUCCESS
1 FAILED
./test-results/mixed-captures-in-expressions-and-postconditions.cpp
./run-tests.sh: line 26: 184219 Segmentation fault      (core dumped) ./$filename >> ./$filename-output 2>&1
./run-tests.sh: line 26: 184231 Aborted                 (core dumped) ./$filename >> ./$filename-output 2>&1
RUN:
31 SUCCESS
2 FAILED
./test-results/mixed-lifetime-safety-and-null-contracts.cpp.out
./test-results/mixed-bounds-safety-with-assert.cpp.out

[hsutter]

Thanks. I'm slowly overhauling the regressing testing to run the tests, and I plan to also do that in bach. I'll defer this until then, I won't get to it immediately but perhaps after the Kona meeting. Again, thanks!

[PastaPastaPasta]

I was actually just beginning to work on a very similar PR, glad I saw this one before I got too into it. I would definitely propose merging this now, and potentially reverting it later when the regression tests are overhauled.

[hsutter]

I've now finished adding support for actually running the regression tests using MSVC, GCC, and Clang. Please see the new stuff under /regression-tests including checked-in results of executing the tests.

I know there's more that could be done, including CI, but for now I'm happy with just running four batch/shell scripts by hand (one to put all the Cpp2 tests through cppfront, and then one each per compiler to build and run the Cpp1 output).

Thanks!