scripted-diff: use insecure_rand256/randrange more

-BEGIN VERIFY SCRIPT-
sed -i "s/\<GetRandHash(/insecure_rand256(/" src/test/*_tests.cpp
sed -i "s/\<GetRand(/insecure_randrange(/" src/test/*_tests.cpp src/test/test_bitcoin.cpp
sed -i 's/\<insecure_rand() % \([0-9]\+\)/insecure_randrange(\1)/g' src/test/*_tests.cpp
-END VERIFY SCRIPT-

src/test/pmt_tests.cpp

@@ -22,7 +22,7 @@ public:
     // flip one bit in one of the hashes - this should break the authentication
     void Damage() {
         unsigned int n = insecure_rand() % vHash.size();
-        int bit = insecure_rand() % 256;
+        int bit = insecure_randrange(256);
         *(vHash[n].begin() + (bit>>3)) ^= 1<<(bit&7);
     }
 };