fix(hiptensor): Move benchmark tests off general ctests

[evedovelli]

Motivation

Running a bare ctest from the installed component dir (/bin/hiptensor) picked up every registered test — including the bench performance runs. Benchmarks are very slow (5 hot runs + 1 cold run per config, plus CPU-reference
validation on every shape), so a plain ctest intended for a quick functional check ended up dominated by benchmark timing loops. The goal is to keep bench out of the default ctest run while still allowing it to be invoked explicitly,
and to stop benchmarks wasting time on validation they don't need.

ISSUE ID : ROCM-30711

Technical Details

• Separate install fragment for bench. Added INSTALL_BENCH_TEST_FILE, emitted to its own bin/hiptensor/bench/CTestTestfile.cmake, mirroring the existing smoke/ and regression/ subdirs. Because the main
  bin/hiptensor/CTestTestfile.cmake does not descend into it, a bare ctest there no longer runs the bench entries. They are opt-in via ctest from /bin/hiptensor/bench (or --test-dir).
• Path fixups for the nested fragment. From bin/hiptensor/bench/ the binary is two levels up (../../) and the shared config subtree is one level up (../configs/bench/...).
• Disable validation on bench runs. The bench command now passes -v OFF. The CPU reference check is far slower than the kernel itself and would otherwise dominate the timing loop.
• The other tiers (quick/standard/comprehensive/full, ffm-*) are unchanged and still run/filter from bin/hiptensor as before.
• Docs (TESTING.md) updated to point bench commands at /bin/hiptensor/bench and note the -v OFF default.

Test Plan and Results

• Configure + build + cmake --install --component tests.
• From /bin/hiptensor: run ctest -N and confirm no * bench entries are listed; run ctest and confirm only regular/tier tests execute.
• From /bin/hiptensor/bench: run ctest -N and ctest --print-labels, confirm the * bench entries appear and carry the bench label; run ctest -V and confirm each invokes ../../ -y ../configs/bench/... -v OFF --hot_runs 5
  --cold_runs 1 and that the config -y path resolves.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/TheRock/blob/main/GOVERNANCE.md#pull-requests.

[therock-pr-bot]

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[therock-pr-bot]

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[Ryker0627]

The changes are good. Worth notice that TESTING.md line 268 and test_categories.yaml line 91 need to update accordingly as well.

[Ryker0627]

LGTM