Revert "[CI][MacOS] Add VENV_PATH to search path (#157749)"

This reverts commit 85111cd165f108ffabb4a90083d59d7a867ebd9f.

Reverted https://github.com/pytorch/pytorch/pull/157749 on behalf of https://github.com/huydhn due to It looks like lint was not green, so revert and reland I guess ([comment](https://github.com/pytorch/pytorch/pull/157749#issuecomment-3047032909))

.github/workflows/_mac-build.yml

@@ -152,14 +152,17 @@ jobs:
         env:
           OUR_GITHUB_JOB_ID: ${{ steps.get-job-id.outputs.job-id }}
         run: |
-          # TODO: Remove me later, and properly activate venv
-          PATH="$VENV_PATH/bin:$PATH"
-          export PATH
+          echo "CMAKE_PREFIX_PATH=${CONDA_PREFIX:-"$(dirname "$(which conda)")/../"}" >> "${GITHUB_ENV}"
+
+          if [[ -n "$CONDA_ENV" ]]; then
+            # Use binaries under conda environment
+            export PATH="$CONDA_ENV/bin":$PATH
+          fi
 
           # NB: Same trick as Linux, there is no need to initialize sccache with the risk of getting
           # it hangs or timeout at initialization. The cache will be started automatically
           export SKIP_SCCACHE_INITIALIZATION=1
-          .ci/pytorch/macos-build.sh
+          ${CONDA_RUN} .ci/pytorch/macos-build.sh
 
       - name: Archive artifacts into zip
         if: inputs.build-generates-artifacts && steps.build.outcome != 'skipped'

.github/workflows/_mac-test.yml

@@ -114,12 +114,6 @@ jobs:
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Setup Python
-        uses: pytorch/test-infra/.github/actions/setup-python@main
-        with:
-          python-version: ${{ inputs.python-version }}
-          pip-requirements-file: .github/requirements/pip-requirements-macOS.txt
-
       - name: Start monitoring script
         id: monitor-script
         if: ${{ !inputs.disable-monitor }}
@@ -132,8 +126,8 @@ jobs:
           MONITOR_LOG_INTERVAL: ${{ inputs.monitor-log-interval }}
           MONITOR_DATA_COLLECT_INTERVAL: ${{ inputs.monitor-data-collect-interval }}
         run: |
-          $VENV_PATH/bin/python3 -m pip install psutil==5.9.1 dataclasses_json==0.6.7
-          $VENV_PATH/bin/python3 -m tools.stats.monitor --log-interval "$MONITOR_LOG_INTERVAL" --data-collect-interval "$MONITOR_DATA_COLLECT_INTERVAL" > usage_log.txt 2>&1 &
+          python3 -m pip install psutil==5.9.1 dataclasses_json==0.6.7
+          python3 -m tools.stats.monitor --log-interval "$MONITOR_LOG_INTERVAL" --data-collect-interval "$MONITOR_DATA_COLLECT_INTERVAL" > usage_log.txt 2>&1 &
           echo "monitor-script-pid=${!}" >> "${GITHUB_OUTPUT}"
 
       - name: Download build artifacts
@@ -148,6 +142,13 @@ jobs:
         with:
           use-gha: true
 
+      - name: Setup Python
+        uses: pytorch/test-infra/.github/actions/setup-python@main
+        with:
+          python-version: ${{ inputs.python-version }}
+          pip-requirements-file: .github/requirements/pip-requirements-macOS.txt
+          default-packages: ""
+
       - name: Parse ref
         id: parse-ref
         run: .github/scripts/parse_ref.py
@@ -198,7 +199,7 @@ jobs:
           set -ex
 
           # TODO: Remove me later, and properly activate venv
-          PATH="$VENV_PATH/bin:$PATH"
+          PATH="$(dirname "$(which python)"):$PATH"
           export PATH
 
           # Print out some information about the test environment