github: Disable fail-fast strategy instead of using continue-on-error

While continue-on-error can be configured more specifically (e.g. also
would allow to handle "default" and "printf-builtin" tests that rely
on debug symbols), it also lets the workflow succeed if any of these
jobs fail.  That's not ideal if there is an actual error and not
just an intermittent package sync problem.

.github/workflows/linux.yml

@@ -32,6 +32,7 @@ jobs:
     if: ${{ needs.pre-check.outputs.should_skip != 'true' }}
     runs-on: ${{ matrix.os || 'ubuntu-latest' }}
     strategy:
+      fail-fast: false
       matrix:
         test: [ all, default, printf-builtin ]
         compiler: [ gcc, clang ]
@@ -101,8 +102,8 @@ jobs:
     needs: pre-check
     if: ${{ needs.pre-check.outputs.should_skip != 'true' }}
     runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ startsWith(matrix.test, 'openssl') }}
     strategy:
+      fail-fast: false
       matrix:
         test: [ botan, wolfssl, openssl, openssl-3, openssl-4, openssl-awslc, gcrypt ]
         os: [ ubuntu-latest, ubuntu-22.04 ]