Run CI for bf16 with custom SDPA (pytorch#5554)

Summary:
Pull Request resolved: pytorch#5554

These configs should work now.

bypass-github-export-checks

Reviewed By: mergennachin

Differential Revision: D63158947

fbshipit-source-id: 92878bb799b311a857db6e12cb6103835514e998

Author: swolchok

.github/workflows/pull.yml

@@ -98,6 +98,12 @@ jobs:
           - dtype: bf16
             build-tool: buck2
             mode: portable
+          - dtype: bf16
+            build-tool: cmake
+            mode: custom
+          - dtype: bf16
+            build-tool: buck2
+            mode: custom
       fail-fast: false
     with:
       runner: linux.2xlarge

.github/workflows/trunk.yml

@@ -227,6 +227,8 @@ jobs:
         include:
           - dtype: bf16
             mode: portable
+          - dtype: bf16
+            mode: custom
       fail-fast: false
     with:
       runner: macos-m1-stable