AWS: fix bugs around using S3FileIO for table operations

[jackye1995]

When used in BaseMetastoreTableOperations, in TableMetadataParser.internalWrite(), an output stream is closed twice because of the closure of the output stream and its writer:

try (OutputStream ou = isGzip ? new GZIPOutputStream(stream) : stream;
         OutputStreamWriter writer = new OutputStreamWriter(ou, StandardCharsets.UTF_8)) {
   ...
}

This causes issue in S3OutputStream because the stream uploads the file from local to S3 during the call to close.

Also, S3FileIO cannot be properly initialized when there are multiple HTTP client builders available in the Java class path at runtime, so AwsClientUtil is used to provide a stable default client for S3FileIO to use.

[rdblue]

Looks good to me, but I'd like to make sure @danielcweeks agrees.

[danielcweeks]

+1 LGTM