Disable CFI for llvm_signal_handler

Bug: http://b/178448317

This function fails cfi check for some reason (the root cause is not
known yet).

Test: Verify llvm_signal_handler symbols in libvpx.so and
      libcodec2_soft_vp8dec.so are not built with CFI.
Change-Id: I50bebf051a60e7a344885934a57205bba6703aba
2 files changed