perf thread: Add support for reading the e_machine type for a thread

perf thread: Add support for reading the e_machine type for a thread

First try to read the e_machine from the dsos associated with the
thread's maps. If live use the executable from /proc/pid/exe and read
the e_machine from the ELF header. On failure use EM_HOST. Change
builtin-trace syscall functions to pass e_machine from the thread
rather than EM_HOST, so that in later patches when syscalltbl can use
the e_machine the system calls are specific to the architecture.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: https://lore.kernel.org/r/20250319050741.269828-8-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>