Make 32 bit CI use x86 Julia build

[visr]

In #1078 I added 13e2055.
That fixed 32 bit CI to use an x86 build of Julia instead of x86_64, as intended. This opened a can of worms in terms of failing tests that I prefer to keep out of #1078, so I reverted it again there.

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e29f506e..1fd5440c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -92,7 +92,7 @@ jobs:
           # If `julia-wordsize` is 64, then we set `arch` to `${{ runner.arch }}`, which
           # GitHub will automatically expand to the correct value (`x86_64` or `aarch64`)
           # based on the architecture of the underlying GitHub Runner (virtual machine).
-          arch: ${{ github.ref == '32' && 'x86' || runner.arch }}
+          arch: ${{ matrix.julia-wordsize == '32' && 'x86' || runner.arch }}
       - uses: julia-actions/cache@d10a6fd8f31b12404a54613ebad242900567f2b9 # v2.1.0
       - uses: julia-actions/julia-runtest@678da69444cd5f13d7e674a90cb4f534639a14f9 # v1.11.2
         with:

diff --git a/.github/workflows/ci.nightly.yml b/.github/workflows/ci.nightly.yml
index 0243adf3..8c961ba2 100644
--- a/.github/workflows/ci.nightly.yml
+++ b/.github/workflows/ci.nightly.yml
@@ -52,7 +52,7 @@ jobs:
           # If `julia-wordsize` is 64, then we set `arch` to `${{ runner.arch }}`, which
           # GitHub will automatically expand to the correct value (`x86_64` or `aarch64`)
           # based on the architecture of the underlying GitHub Runner (virtual machine).
-          arch: ${{ github.ref == '32' && 'x86' || runner.arch }}
+          arch: ${{ matrix.julia-wordsize == '32' && 'x86' || runner.arch }}
       - uses: julia-actions/cache@d10a6fd8f31b12404a54613ebad242900567f2b9 # v2.1.0
       - uses: julia-actions/julia-runtest@678da69444cd5f13d7e674a90cb4f534639a14f9 # v1.11.2
         with: