testsuite: silence nolto-rel warning in pr62026_0.C

On some targets, pr62026_0.C issues a warning about implicitly passing
-flinker-output=nolto-rel, which flags the test as a failure.  Pass
the flag explicitly to avoid the warning.

for  gcc/testsuite/ChangeLog

	* g++.dg/lto/pr62026_0.C: Silence -flinker-output warning.

(cherry picked from commit b9171f4eff5611bec4eadcae9095ce2e7bf0937d)