REGTESTS: quic: issuers_chain_path.vtc supported by QUIC

REGTESTS: quic: issuers_chain_path.vtc supported by QUIC

ssl/issuers_chain_path.vtc was rename to ssl/issuers_chain_path.vtci
to produce a common part runnable both for QUIC and TCP connections.
Then issuers_chain_path.vtc files were created both under ssl and quic directories
to call this .vtci file with correct VTC_SOCK_TYPE environment values
("quic" for QUIC connection and "stream" for TCP connections);