ci: only run BN and Ghidra tests after others complete

these are much less likely to fail because they're
changed less often, so don't run them until we know
other tests also pass.

.github/workflows/tests.yml

@@ -107,7 +107,7 @@ jobs:
     env:
       BN_SERIAL: ${{ secrets.BN_SERIAL }}
     runs-on: ubuntu-20.04
-    needs: [code_style, rule_linter]
+    needs: [tests]
     strategy:
       fail-fast: false
       matrix:
@@ -147,7 +147,7 @@ jobs:
   ghidra-tests:
     name: Ghidra tests for ${{ matrix.python-version }}
     runs-on: ubuntu-20.04
-    needs: [code_style, rule_linter]
+    needs: [tests]
     strategy:
       fail-fast: false
       matrix:
@@ -201,4 +201,4 @@ jobs:
         cat ../output.log
         exit_code=$(cat ../output.log | grep exit | awk '{print $NF}')
         exit $exit_code
- 
+