Disable runningcheck for src/test/modules/injection_points/specs.

Disable runningcheck for src/test/modules/injection_points/specs.

Directory "injection_points" has specified NO_INSTALLCHECK since before
commit c35f419d6efbdf1a050250d84b687e6705917711 added the specs, but
that commit neglected to disable the corresponding meson runningcheck.
The alternative would be to enable "make installcheck" for ISOLATION,
but the GNU make build system lacks a concept of setting NO_INSTALLCHECK
for REGRESS without also setting it for ISOLATION.  Back-patch to v17,
where that commit first appeared, to avoid surprises when back-patching
additional specs.

Discussion: https://postgr.es/m/17821-dd8c334263399284@postgresql.org