PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS

This pulls in the following LLVM changes:

43d482a: (dschuff@chromium.org) Use R0/R1 instead of R4/R5 for ARM eh_return return values
78eed07: (kschimpf@google.com) Fix writing of blockinfo blocks when bitcode munging.
d2a9f29: (reed.kotler@imgtec.com) Add mips32 to LLVM configure's list of allowed Subzero targets.
25718c2: (dschuff@chromium.org) Revert "Use R0/R1 instead of R4/R5 for ARM eh_return return values"
7aaca46: (jvoung@chromium.org) SimplifyAllocas: search through more bitcasts to find alloca for llvm.dbg.declare.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4169
BUG= https://code.google.com/p/nativeclient/issues/detail?id=4167
BUG= https://code.google.com/p/nativeclient/issues/detail?id=4203
TEST= PNaCl toolchain trybots
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/1173383005.

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client