ci: run test builds on 16 GiB portable runners (#607)

Building SIMPLE's tests generates \`wout_ncsx.chartmap.nc\`
(\`test/tests/CMakeLists.txt:318-324\`) with libneo's
\`vmec_to_chartmap.x\`. The VMEC spline tables behind it peak at 10.3 GB
RSS; this was measured locally with libneo main 7d2e1a8 and does not
depend on thread count. On the 10 GiB \`local-portable-itpplasma-1\`
slot the process is OOM-killed (\`Killed\`). This happened in the VMEC++
and CGAL jobs of runs 39678368766, 39696544349, 39696548698 and
39696550366, and only on that slot.

This PR makes every job that builds the test suite request
\`itp-mem16\`: the portable \`Build and Test\` path, GCC matrix, ifx,
flang, CGAL, VMEC++ and the verification report.

`itp-mem16` comes from
[itp-infra](https://github.com/itpplasma/itp-infra) PR #14 (merged
e4edfb69); the KUB portable slots now register with it.

Author: krystophny

.github/workflows/main.yml

@@ -90,7 +90,7 @@ jobs:
   test:
     name: Build and Test
     runs-on: >-
-      ${{ (github.event_name == 'pull_request' || inputs.runner == 'portable' || inputs.runner == 'hosted') && fromJSON('["self-hosted","itp-ubuntu24"]') || fromJSON('["self-hosted","itp-dispatch"]') }}
+      ${{ (github.event_name == 'pull_request' || inputs.runner == 'portable' || inputs.runner == 'hosted') && fromJSON('["self-hosted","itp-ubuntu24","itp-mem16"]') || fromJSON('["self-hosted","itp-dispatch"]') }}
     timeout-minutes: 150
     env:
       OMP_NUM_THREADS: 2
@@ -283,6 +283,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     timeout-minutes: 45
     if: >-
       (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.actor != 'github-merge-queue[bot]')) && ((github.event_name == 'merge_group' || (github.event_name == 'workflow_dispatch' && inputs.full == 'true') || (github.event_name == 'pull_request' && github.event.pull_request.draft == false)) && (github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'full-ci')))
@@ -337,6 +338,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     if: >-
       (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.actor != 'github-merge-queue[bot]')) && (github.event_name == 'workflow_dispatch' && inputs.experimental_compilers)
     continue-on-error: true
@@ -385,6 +387,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     if: >-
       (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.actor != 'github-merge-queue[bot]')) && (github.event_name == 'workflow_dispatch' && inputs.experimental_compilers)
     continue-on-error: true
@@ -426,6 +429,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     if: >-
       (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.actor != 'github-merge-queue[bot]')) && (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || github.event_name == 'pull_request')
 
@@ -500,6 +504,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     if: >-
       (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.actor != 'github-merge-queue[bot]')) && ((github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' || (github.event_name == 'pull_request' && github.event.pull_request.draft == false)) && (github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'full-ci')))
 
@@ -590,6 +595,7 @@ jobs:
     runs-on:
       - self-hosted
       - itp-ubuntu24
+      - itp-mem16
     timeout-minutes: 20
     permissions:
       contents: read