Regenerated cross-compiled arch flag test binaries

This was needed after an update to goto-cc, which caused
previously-compiled binaries used in the test suite to trigger an
assertion failure. Also updated instructions on how to generate these
binaries.

This commit fixes diffblue#1376.

Author: karkhaz

regression/ansi-c/arch_flags_mcpu_bad/object.intel

@@ -12,12 +12,17 @@ The object file 'object.arm' was compiled from 'source.c' with goto-cc
 along with an ARM cross-compiler on a 64-bit platform with the following
 command line:
 
-  goto-cc --native-compiler=arm-none-eabi-gcc -mcpu=cortex-a15 -c source.c
+  goto-cc -o object.arm --native-compiler=arm-none-eabi-gcc -mcpu=cortex-a15 -c source.c
 
-On Ubuntu, you can get a suitable compiler using:
+To regenerate object.arm on an x86_64 machine, you will need to install
+an ARM-32 cross compiler and pass the name of that compiler to the
+--native-compiler flag. On Ubuntu, you can get a suitable compiler
+using:
 
   sudo apt install gcc-arm-none-eabi
 
+which will install arm-none-eabi-gcc (amongst other things).
+
 preproc.i is already pre-processed so that it can be linked in without
 needing to invoke a pre-processor from a cross-compile toolchain on your
 local machine. Linking it together with the ARM object file, while

regression/ansi-c/arch_flags_mcpu_good/object.arm

@@ -12,12 +12,17 @@ file 'object.arm' was compiled from 'source.c' with goto-cc along with
 an ARM cross-compiler on a 64-bit platform with the following command
 line:
 
-  goto-cc --native-compiler=arm-none-eabi-gcc -mthumb -c source.c
+  goto-cc -o object.arm --native-compiler=arm-none-eabi-gcc -mthumb -c source.c
 
-On Ubuntu, you can get a suitable compiler using:
+To regenerate object.arm on an x86_64 machine, you will need to install
+an ARM-32 cross compiler and pass the name of that compiler to the
+--native-compiler flag. On Ubuntu, you can get a suitable compiler
+using:
 
   sudo apt install gcc-arm-none-eabi
 
+which will install arm-none-eabi-gcc (amongst other things).
+
 preproc.i is already pre-processed so that it can be linked in without
 needing to invoke a pre-processor from a cross-compile toolchain on your
 local machine. Linking it together with the ARM object file, while