CI: Leave out unnecessary build files from binary artifact (#9135)

The pg_install/build directory contains .o files and such intermediate
results from the build, which are not needed in the final tarball.
Except for src/test/regress/regress.so and a few other .so files in that
directory; keep those.

This reduces the size of the neon-Linux-X64-release-artifact.tar.zst
artifact from about 1.5 GB to 700 MB.

(I attempted this a long time ago already, by moving the build/
directory out of pg_install altogether, see PR #2127. But I never got
around to finish that work.)

Co-authored-by: Alexander Bayandin <alexander@neon.tech>

.github/workflows/_build-and-test-locally.yml

@@ -257,7 +257,15 @@ jobs:
           ${cov_prefix} cargo nextest run $CARGO_FLAGS $CARGO_FEATURES -E 'package(remote_storage)' -E 'test(test_real_azure)'
 
       - name: Install postgres binaries
-        run: cp -a pg_install /tmp/neon/pg_install
+        run: |
+          # Use tar to copy files matching the pattern, preserving the paths in the destionation
+          tar c \
+            pg_install/v* \
+            pg_install/build/*/src/test/regress/*.so \
+            pg_install/build/*/src/test/regress/pg_regress \
+            pg_install/build/*/src/test/isolation/isolationtester \
+            pg_install/build/*/src/test/isolation/pg_isolation_regress \
+            | tar  x -C /tmp/neon
 
       - name: Upload Neon artifact
         uses: ./.github/actions/upload