Move storgae greentea test

Author: rajkan01

storage/TESTS/blockdevice/buffered_block_device/main.cpp renamed to storage/blockdevice/tests/TESTS/blockdevice/buffered_block_device/main.cpp

@@ -192,4 +192,3 @@ int main()
 {
     return !Harness::run(specification);
 }
-

storage/TESTS/blockdevice/flashsim_block_device/main.cpp renamed to storage/blockdevice/tests/TESTS/blockdevice/flashsim_block_device/main.cpp

@@ -34,7 +34,7 @@ Use `mbed test` again:
 ```
 mbed test -m K64F -t ARM -n mbed-os-features-storage-tests-blockdevice-general_block_device --run -v
 ```
-   
+
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