[llvm] [gold] Don't hardcode section index in test (PR #222339)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-mlir-rhel-clang` running on `ppc64le-mlir-rhel-test` while building `llvm` at step 6 "test-build-check-mlir-build-only-check-mlir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/129/builds/52226

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-check-mlir-build-only-check-mlir) failure: 1200 seconds without output running [b'ninja', b'check-mlir'], attempting to kill
...
PASS: MLIR-Unit :: Dialect/OpenACC/./MLIROpenACCTests/7/193 (4599 of 4608)
PASS: MLIR-Unit :: Dialect/OpenACC/./MLIROpenACCTests/70/193 (4600 of 4608)
PASS: MLIR-Unit :: Dialect/OpenACC/./MLIROpenACCTests/9/193 (4601 of 4608)
PASS: MLIR-Unit :: Dialect/OpenACC/./MLIROpenACCTests/90/193 (4602 of 4608)
PASS: MLIR :: mlir-runner/simple.mlir (4603 of 4608)
PASS: MLIR :: mlir-runner/test-expand-math-approx.mlir (4604 of 4608)
PASS: MLIR :: mlir-tblgen/llvm-intrinsics.td (4605 of 4608)
PASS: MLIR :: mlir-tblgen/method-body-with-only-spaces.td (4606 of 4608)
PASS: MLIR :: Pass/pipeline-options-parsing.mlir (4607 of 4608)
PASS: MLIR :: Pass/pipeline-parsing.mlir (4608 of 4608)
command timed out: 1200 seconds without output running [b'ninja', b'check-mlir'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=2319.222587

```

</details>

https://github.com/llvm/llvm-project/pull/222339