Increase iterations for some statistical tests

I ran into a sequence where the assertion `stats[8] > 0` failed for the
range 1..272 with 100 iterations.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_bignum.misc.data b/tests/suites/test_suite_bignum.misc.data
index 78afcb6..29ba4ab 100644
--- a/tests/suites/test_suite_bignum.misc.data
+++ b/tests/suites/test_suite_bignum.misc.data
@@ -1766,16 +1766,16 @@
 mpi_random_many:1:"0c":1000
 
 MPI random in range: 1..255
-mpi_random_many:1:"ff":100
+mpi_random_many:1:"ff":200
 
 MPI random in range: 1..256
-mpi_random_many:1:"0100":100
+mpi_random_many:1:"0100":200
 
 MPI random in range: 1..257
-mpi_random_many:1:"0101":100
+mpi_random_many:1:"0101":200
 
 MPI random in range: 1..272
-mpi_random_many:1:"0110":100
+mpi_random_many:1:"0110":200
 
 MPI random in range: 1..2^64-1
 mpi_random_many:1:"ffffffffffffffff":100