NaCl: Update revision in DEPS, r13456 -> r13484

This pulls in the following Native Client changes:

r13457: (dyen) LLVM Regression tests check for build files instead of empty dirs.
r13458: (noelallen) Update and add GN files to build sel_ldr.
r13459: (jvoung) Remove env cleanser references to obsolete env vars.
r13460: (jfb) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13461: (hamaji) Non-SFI Mode: Add prctl syscall wrapper
r13462: (hamaji) Non-SFI Mode: Implement IRT fstat
r13463: (hamaji) Correct the return type of TestSuite in timefuncs_test
r13464: (hamaji) syscall_test: Do not test st_atime in the test for fstat
r13465: (earthdok) Implement initial MSan support. Also, adjust ASan build flags.
r13466: (dschuff) pnacl-ld: Do not attempt to parse ELF or bitcode files as linker scripts
r13467: (jvoung) Remove NaClSrpcIsStandalone() function.
r13468: (dschuff) Make testing architecture explicit PNaCl toolchain buildbot script
r13469: (dschuff) Stub out pnacl-opt and pnacl-finalize tools for scons built_elsewhere=1
r13470: (dschuff) Update revision for PNaCl r13392->r13466
r13471: (noelallen) Build nacl_bootstrap_helper and test with GN scons
r13472: (dschuff) Build PNaCl with mingw again
r13473: (earthdok) Zap the NaClSignalContext struct in SignalCatch.
r13474: (dschuff) Update revision for PNaCl r13466->r13472
r13475: (sehr) Munge nacl_helper_bootstrap using python rather than libelf
r13476: (sky) Changes scan_sources not to output on bogus directory
r13477: (dschuff) Reduce debugging metadata for pexe builds in Chrome
r13480: (jfb) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13481: (hidehiko) Align at 16 bytes for stack for created thread.
r13484: (jfb) Revert "Munge nacl_helper_bootstrap using python rather than libelf"

BUG=none
TEST=browser_tests and nacl_integration
R=jvoung@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283271

Review URL: https://codereview.chromium.org/390553002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283448 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -35,7 +35,7 @@ vars = {
   "skia_git": "https://skia.googlesource.com",
   "boringssl_git": "https://boringssl.googlesource.com",
   "swig_revision": "230490",
-  "nacl_revision": "13456",
+  "nacl_revision": "13484",
   # After changing nacl_revision, run 'glient sync' and check native_client/DEPS
   # to update other nacl_*_revision's.
   "nacl_tools_revision": "13077",  # native_client/DEPS: tools_rev