[static analysis] Buffer Overflow boundcpy WrongSizeParam

[DonnaWuDongxia]

The size of the buffer used by Buffer::getArrayBuffer in size, at line 15 of /widl-nanmaster/
test/buffer/buffer.cpp, is not properly verified before writing data to the buffer. This can enable a buffer
overflow attack, using the source buffer that Buffer::getArrayBuffer passes to size, at line 15 of /widl-nanmaster/
test/buffer/buffer.cpp, to overwrite the target buffer.

Code Snippet
File Name /widl-nan-master/test/buffer/buffer.cpp
Method ArrayBuffer Buffer::getArrayBuffer() const {

....
21. memcpy(buf, text, size);

[DonnaWuDongxia]

@kenny-y would you please take a look at it?