perf python: split Clang options when invoking Popen

perf python: split Clang options when invoking Popen

When passing a list to subprocess.Popen, each element maps to one argv
token. Current code bundles multiple Clang flags into a single element,
something like:

  cmd = ['clang',
         '--target=x86_64-linux-gnu -fintegrated-as -Wno-cast-function-type-mismatch',
	 'test-hello.c']

So Clang only sees one long, invalid option instead of separate flags,
as a result, the script cannot capture any log via PIPE.

Fix this by using shlex.split() to separate the string so each option
becomes its own argv element. The fixed list will be:

  cmd = ['clang',
         '--target=x86_64-linux-gnu',
	 '-fintegrated-as',
	 '-Wno-cast-function-type-mismatch',
	 'test-hello.c']

Fixes: 09e6f9f98370 ("perf python: Fix splitting CC into compiler and options")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20251006-perf_build_android_ndk-v3-2-4305590795b2@arm.com
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: linux-riscv@lists.infradead.org
Cc: llvm@lists.linux.dev
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>