LU-13485 build: Parallel build configure cache fixes

LU-13485 build: Parallel build configure cache fixes

This fixes the infrastructure for parallel builds when cached
enabled results are enabled, the critical fix being proper
usage of AC_CACHE_CHECK in the LB2_LINUX_TEST_RESULT macro.

Lustre-change: https://review.whamcloud.com/49149
Lustre-commit: 24c9f1f4c56d266656572e7bd97197d690d49369

Test-Parameters: trivial
Fixes: b0209c2d4d ("LU-13485 build: Enable 2 stage configure tests")
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I94d7ff291dfd4f2dc5e218acc811329b986f8fbf
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/49853
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>