Add explicit UTF-8 charset to InputStreamReader in StdioServerTransportProvider #152

Job	Run time
Server Conformance	1m 15s
Client Conformance (initialize)	1m 15s
Client Conformance (elicitation-sep1034-client-defaults)	1m 4s
Auth Conformance (auth/scope-from-www-authenticate)	1m 13s
Client Conformance (sse-retry)	1m 10s
Auth Conformance (auth/token-endpoint-auth-post)	1m 18s
Auth Conformance (auth/token-endpoint-auth-basic)	1m 14s
Auth Conformance (auth/metadata-default)	1m 11s
Client Conformance (tools_call)	1m 4s
Auth Conformance (auth/scope-from-scopes-supported)	1m 18s
Auth Conformance (auth/scope-retry-limit)	1m 19s
Auth Conformance (auth/metadata-var1)	1m 20s
Auth Conformance (auth/pre-registration)	1m 22s
Auth Conformance (auth/basic-cimd)	1m 6s
Auth Conformance (auth/scope-step-up)	1m 24s
Auth Conformance (auth/metadata-var2)	1m 14s
Auth Conformance (auth/metadata-var3)	1m 23s
Auth Conformance (auth/scope-omitted-when-undefined)	1m 17s
Auth Conformance (auth/token-endpoint-auth-none)	1m 9s
	23m 36s

Provide feedback