build: Remove functional_tests= option

We should always enable these. The only dependency added a configure
time is Python which our build system already requires.

Some tests will fail in certain build configurations, such as if
PyGObject is not available. That's expected, and if it's a problem
for you then try:

    meson test --no-suite=functional ...

Partial fix for #162
4 jobs for sam/functional-tests-always in 12 minutes and 18 seconds (queued for 17 minutes and 10 seconds)
latest
Status Job ID Name Coverage
  Test
failed #1350392
test-fedora-latest

00:05:28

failed #1350393
test-fedora-rawhide

00:06:19

failed #1350394
test-ubuntu-rolling

00:06:14

 
  Analysis
skipped #1350395
allowed to fail
coverage-analysis
 
Name Stage Failure
failed
test-ubuntu-rolling Test
Uploading artifacts for failed job
Uploading artifacts...
build/meson-logs/*.txt: found 2 matching files and directories

Uploading artifacts as "archive" to coordinator... ok
id=1350394 responseStatus=201 Created token=WUveVvbc
Uploading artifacts...
build/meson-logs/testlog.junit.xml: found 1 matching files and directories

Uploading artifacts as "junit" to coordinator... ok
id=1350394 responseStatus=201 Created token=WUveVvbc
Cleaning up file based variables
ERROR: Job failed: exit code 1
failed
test-fedora-latest Test
Uploading artifacts for failed job
Uploading artifacts...
build/meson-logs/*.txt: found 2 matching files and directories

Uploading artifacts as "archive" to coordinator... ok
id=1350392 responseStatus=201 Created token=4STux9wJ
Uploading artifacts...
build/meson-logs/testlog.junit.xml: found 1 matching files and directories

Uploading artifacts as "junit" to coordinator... ok
id=1350392 responseStatus=201 Created token=4STux9wJ
Cleaning up file based variables
ERROR: Job failed: exit code 1
failed
test-fedora-rawhide Test
Uploading artifacts for failed job
Uploading artifacts...
build/meson-logs/*.txt: found 2 matching files and directories

Uploading artifacts as "archive" to coordinator... ok
id=1350393 responseStatus=201 Created token=GLF-J-a7
Uploading artifacts...
build/meson-logs/testlog.junit.xml: found 1 matching files and directories

Uploading artifacts as "junit" to coordinator... ok
id=1350393 responseStatus=201 Created token=GLF-J-a7
Cleaning up file based variables
ERROR: Job failed: exit code 1