[build]: Reduce duplicate compilation in CI

[theasianpianist]

Why

Recent SWSS jobs are approaching or exceeding the 60-minute CI timeout. Azure logs showed ASAN compilation at 48-53 minutes and Trixie compilation varying from 33 minutes to over 53 minutes. A timed-out Trixie job spent 32.6 minutes in orchagent compilation and another 9.7 minutes compiling mock tests before cancellation.

What changed

• Build common cfgmgr framework sources once in libcfgmgrcommon.a instead of once per daemon.
• Build production sources shared by orchagent and P4 tests once in libp4orchshared.a.
• Keep P4 test-only sources at -O0 while production objects retain the package optimization level.
• Convert unit-test binaries from noinst_PROGRAMS to check_PROGRAMS.
• Use DEB_BUILD_OPTIONS=nocheck for Trixie package jobs, while primary Bookworm and ASAN jobs retain unit-test execution.
• Skip test-result publishing for jobs that intentionally do not run unit tests.

Measured impact

In a container constrained to the CI agents' 4 CPUs and 32 GiB:

Build	Before	After
Default package build with tests	28:58 / 644 C++ compilations	26:12 / 552 compilations
Trixie-style nocheck package build	28:58 / 644 compilations	11:45 / 199 compilations
ASAN P4 test build/run	10:24	5:43

Validation

• Rebased onto current master (4f3dda15).
• Exact package command completed successfully in 24:04:
  • ./autogen.sh
  • RUSTFLAGS=-Dwarnings dpkg-buildpackage -us -uc -b -j$(nproc)
• All C++ test suites passed with zero failures.
• GCOV tests, coverage collection, and package generation completed successfully.
• Trixie-style DEB_BUILD_OPTIONS=nocheck package generation completed successfully.
• ASAN P4 tests completed successfully.
• Verified no-op orchagent builds do not relink, while changes to shared sources rebuild the archive and relink in one invocation.

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines:
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[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).

[Copilot]

Pull request overview

This PR optimizes the SWSS autotools build and Azure CI pipeline to reduce duplicate compilations (notably in orchagent/P4 and cfgmgr paths) and keep CI runtimes under timeout by reusing newly introduced static convenience archives and selectively skipping unit-test execution in Trixie package builds.

Changes:

• Introduce reusable static archives (libcfgmgrcommon.a, libp4orchshared.a) to compile shared sources once and link them into multiple binaries.
• Move unit-test binaries from noinst_PROGRAMS to check_PROGRAMS so they compile only during make check (and can be skipped via DEB_BUILD_OPTIONS=nocheck).
• Add an Azure pipeline parameter to disable unit tests for Trixie package builds and skip publishing test results when tests are intentionally not run.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/mock_tests/Makefile.am	Switch unit-test targets to check_PROGRAMS to avoid building them during the normal make all path.
tests/Makefile.am	Convert the tests binary to check_PROGRAMS so it builds/runs only under make check.
orchagent/p4orch/tests/Makefile.am	Add libp4orchshared.a and link it into p4orch_tests; keep test-only objects at -O0.
orchagent/p4orch/shared_sources.mk	Define a shared source list for orchagent/P4 code to be compiled once into an archive.
orchagent/Makefile.am	Link orchagent against the shared archive and add build dependency wiring.
configure.ac	Add AM_PROG_AR to support building new static archives reliably.
cfgmgr/Makefile.am	Build common cfgmgr framework sources once as libcfgmgrcommon.a and link it into cfgmgr daemons.
azure-pipelines.yml	Disable unit tests in the Trixie build stages via a new template parameter.
.azure-pipelines/build-template.yml	Implement run_unit_tests parameter: set DEB_BUILD_OPTIONS=nocheck when false and gate test publishing accordingly.