Correct for signal, native bridge test hard-coded signal handling values

Added inline assembly to ensure that the instruction causing a segfault
in x86/x86_64 for the 004-SignalTest and 115-native-bridge test always
has a size of 3 bytes, in response to a bug that caused the test to fail
when this instruction had variable sizes.

Bug: 22876261
Change-Id: I474a04782a446439956c22360c71cea2655f8a1b