gnu: nss/fixed: Hasten test suite.

This causes the test suite to run in about in nearly a third of the original
time (from 145 min to 52 minutes on a particular machine).

* gnu/packages/nss.scm (nss/fixed) [phases] {check}: Set NSS_CYCLES
environment variable to 'standard'.

Change-Id: I5dab1ed16b302af2276b0f075a790f6193edbe95

gnu/packages/nss.scm

@@ -288,6 +288,11 @@ security standards.")
                          (substitute* "nss/tests/dbtests/dbtests.sh"
                            ((" -lt 5") " -lt 50"))
 
+                         ;; Since the test suite is very lengthy, run the test
+                         ;; suite once, not thrice as done by default, by
+                         ;; selecting only the 'standard' cycle.
+                         (setenv "NSS_CYCLES" "standard")
+
                          ;; The "PayPalEE.cert" certificate expires every six months,
                          ;; leading to test failures:
                          ;; <https://bugzilla.mozilla.org/show_bug.cgi?id=609734>.  To