Fix general block device test to ensure unique block address per test

Author: offirko

features/storage/TESTS/blockdevice/general_block_device/main.cpp

@@ -187,6 +187,11 @@ void basic_erase_program_read_test(BlockDevice *block_device, bd_size_t block_si
 {
     int err = 0;
     _mutex->lock();
+
+    // Make sure block address per each test is unique
+    static unsigned block_seed = 1;
+    srand(block_seed++);
+
     // Find a random block
     bd_addr_t block = (rand() * block_size) % (block_device->size());