[SystemZ] Add missing isBranch flags to certain instruction

Some instructions were missing isBranch, isCall, or isTerminator
flags.  This didn't really affect code generation since most of
the affected patterns were used only for the AsmParser and/or
disassembler.

However, it could affect tools using the MC layer to disassemble
and parse binary code (e.g. via MCInstrDesc::mayAffectControlFlow).

llvm-svn: 263478