Use non-cron builds on travis

Per https://docs.travis-ci.com/user/billing-overview/#partner-queue-solution
it's possible to use arm64, ppc64le and s390x without consuming
credits, as these are part of "Partner Queue Solution".

Try running these jobs unconditionally, rather than as cron jobs.
This also requires switching from arm64-graviton2 back to arm64,
as this doesn't seem to extend to arm64-graviton2.

Author: nikic

.travis.yml

@@ -69,14 +69,9 @@ env:
 jobs:
     include:
         - env: ENABLE_ZTS=1 ENABLE_DEBUG=1 SKIP_IO_CAPTURE_TESTS=1 ARM64=1
-          arch: arm64-graviton2
-          dist: bionic
-          virt: lxd
-          group: edge
-          if: type = cron
+          arch: arm64
         - env: ENABLE_ZTS=1 ENABLE_DEBUG=1 SKIP_IO_CAPTURE_TESTS=1 S390X=1
           arch: s390x
-          if: type = cron
 
 before_script:
     - ccache --version