Run CI for bf16 with custom SDPA (#5554)

Summary:

These configs should work now.

Reviewed By: mergennachin

Differential Revision: D63158947

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