NaCl: Update revision in DEPS, r9843 -> r9864

NaCl: Update revision in DEPS, r9843 -> r9864

This pulls in the following Native Client changes:

r9844: (shcherbina) Validator testing: add option '--update' to regenerate golden fields in .test files.
r9845: (olonho) Build NaCl for Android/ARM.
r9846: (mseaborn) Debug stub tests: Extend to test more register values
r9847: (mseaborn) Debug stub tests: Remove the remaining test that uses int3
r9848: (mseaborn) Debug stub: Make socket binding coexist with the outer sandbox on Mac
r9849: (mcgrathr) Fix two "variable may be used uninitialized" warnings
r9850: (khim) Remove dot from gen_dfa-generated files.
r9851: (khim) Add end-to-end tests to gen_dfa.cc
r9852: (dschuff) Update llvm and clang revs to pull in merge to 164479
r9853: (phosek) Secure command channel and untrusted application channel have been split as two separated socket addresses, this allows secure command channel address to be passed to parent, etc.
r9854: (mcgrathr) Add testdata files for unaligned_data_irt test
r9855: (phosek) Mprotect syscall implemented.
r9856: (shcherbina) Validator testing: add code to run rdfa validator
r9857: (mcgrathr) Tweak x86-32 testdata file for unaligned_data_irt test
r9858: (mseaborn) Cleanup: Remove PpapiPluginRegisterDefaultThreadCreator()
r9859: (halyavin) Remove timeout for waiting packet data. Add buffering to transport class.
r9860: (mcgrathr) Make ARM dyncode illegal-call-target test compatible with GAS
r9861: (mcgrathr) Do not require IRT writable data segment to be page-aligned
r9862: (phosek) Untrusted application channel argument added to CreateProcess interface.
r9863: (kschimpf) Clean up dynamic code modification support in ARM validator.
r9864: (mseaborn) PNaCl: Remove -DNACL_LINUX=1 from the driver script

BUG=none
TEST=nacl_integration