Revert "Build ubench in CI (#305)" (#335)

This reverts commit 59d5b51.

### Issue
No issue

### Description
Previous PR broke tt_metal build:
https://github.com/tenstorrent/tt-metal/actions/runs/12030573411

### List of the changes
- git revert 59d5b51

### Testing
This issue doesn't show up in tt_metal post commit after this revert:
https://github.com/tenstorrent/tt-metal/actions/runs/12030762771

### API Changes
There are no API changes in this PR.

.github/workflows/build-tests.yml

@@ -28,7 +28,7 @@ on:
 
 
 env:
-  BUILD_TARGETS: "umd_tests ubench"
+  BUILD_TARGET: umd_tests
   BUILD_OUTPUT_DIR: ./build
   LIB_OUTPUT_DIR: ./build/lib
   DEPS_OUTPUT_DIR: ./build/_deps
@@ -62,11 +62,11 @@ jobs:
           submodules: recursive
           lfs: 'true'
 
-      - name: Build ${{ env.BUILD_TARGETS }}
+      - name: Build ${{ env.BUILD_TARGET }}
         run: |
           echo "Compiling the code..."
           cmake -B ${{ env.BUILD_OUTPUT_DIR }} -G Ninja -DTT_UMD_BUILD_TESTS=ON
-          cmake --build ${{ env.BUILD_OUTPUT_DIR }} --target ${{ env.BUILD_TARGETS }}
+          cmake --build ${{ env.BUILD_OUTPUT_DIR }} --target ${{ env.BUILD_TARGET }}
           echo "Compile complete."
 
       # This is needed to preserve file permissions

tests/CMakeLists.txt

@@ -58,7 +58,9 @@ else()
     include_directories("${CMAKE_CURRENT_BINARY_DIR}/$ENV{ARCH_NAME}")
 endif()
 
-add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/microbenchmark)
+if(MASTER_PROJECT)
+    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/microbenchmark)
+endif()
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/api)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/pcie)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/misc)