CI: simplify steps for using in-repo please_pex tool

The circular dependency between please_pex and its bootstrap archive
was broken in please-build#266, allowing for the plugin to be configured to use
`//tools_please_pex` as its own pex tool. This is simpler than building
the please_pex binary in one step, copying it elsewhere in the file
system for persistence, then configuring future steps to use that binary
as the pex tool.

Author: chrisnovakovic

.github/workflows/plugin_test.yaml

@@ -38,13 +38,10 @@ jobs:
       - name: Configure plugin's default Python interpreter
         run: |
           echo "PLZ_ARGS=-o plugin.python.defaultinterpreter:${{ steps.python.outputs.python-path }}" >> $GITHUB_ENV
-      - name: Build please_pex
+      - name: Configure plugin to use please_pex tool built from source
         if: inputs.please_pex_from_repo
-        # This copies the please_pex binary into the runner user's home directory so it persists across steps.
         run: |
-          ./pleasew build //tools/please_pex
-          cp $(./pleasew query outputs //tools/please_pex) $HOME/please_pex
-          echo "PLZ_ARGS="$(grep ^PLZ_ARGS= $GITHUB_ENV | cut -d= -f2-)" -o plugin.python.pextool:$HOME/please_pex" >> $GITHUB_ENV
+          echo "PLZ_ARGS="$(grep ^PLZ_ARGS= $GITHUB_ENV | cut -d= -f2-)" -o plugin.python.pextool://tools/please_pex" >> $GITHUB_ENV
       - name: Run tests
         run: ./pleasew test --keep_going --log_file plz-out/log/test.log ${{ inputs.test_targets }}
       - name: Archive logs

.gitignore

@@ -1,5 +1,3 @@
-tools/please_pex_dev
-
 # Entries below this point are managed by Please (DO NOT EDIT)
 plz-out
 .plzconfig.local

.plzconfig.tool_dev

@@ -13,16 +13,3 @@ remote_file(
     binary = True,
     visibility = ["PUBLIC"],
 )
-
-# This target is only intended for use during plugin development. Its only purpose is to break the
-# mutual dependency between please_pex and the python_wheels in the bootstrap pex, which prevents
-# PexTool from being set to //tools/please_pex in order to test changes to please_pex.
-#
-# See .plzconfig.tool_test for more details.
-filegroup(
-    name = "please_pex_dev",
-    srcs = ["please_pex_dev"],
-    binary = True,
-    labels = ["manual"],
-    visibility = ["PUBLIC"],
-)