perf inject/aslr: Implement sample address remapping

perf inject/aslr: Implement sample address remapping

Add the sample address remapping logic to the ASLR tool. This patch
implements aslr_tool__process_sample, which parses sample events,
remaps IPs, ADDRs, callchains, and branch stacks using the mappings
collected from metadata events, and drops potentially leaking raw,
register, stack, physical address, and aux samples.

Also adds the aslr_tool__remap_address helper function.

Note on cross-endian compatibility:
'perf inject' functions as an endianness converter. Input files are read,
and their events are byte-swapped to host endianness in memory. When the
tool emits its output, it writes a host-endian PERF_MAGIC in the file
header, thereby marking the output file as host-endian natively.

Because the output file is always written in host endianness, events and
payloads must be constructed entirely using host-endian layouts. For this
reason, this patch explicitly un-packs and repacks PERF_SAMPLE_TID (and
PERF_SAMPLE_CPU) using unions to ensure that the sequential 32-bit layout
is correctly aligned in host endianness. Similarly, branch stack flags
(which are modified in-place to host-endian bitfields by the parser) are
copied directly to the newly synthesized event. When re-parsing the newly
synthesized event, 'needs_swap=false' is explicitly used to prevent double
swapping the already host-endian fields.

Committer notes:

Removed several unused variables, they will be reintroduced in the
following patches where they are finally used:

	struct aslr_evsel_priv *priv = NULL;
	u64 orig_sample_type;
	u64 orig_regs_user;
	u64 orig_regs_intr;

Also used PRIx64 for two u64 args (addresses) and %zu for a size_t arg
(map__size()) to fix the build on 32-bit architectures.

Assisted-by: Antigravity:gemini-3.1-pro
Co-developed-by: Gabriel Marin <gmx@google.com>
Signed-off-by: Gabriel Marin <gmx@google.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>