tests: Fix up to work on arbitrary architectures

The current test infrastructure is tied to x86/amd64.  This means the
tests always fail on a non-x86 architecture (like aarch64).  Fix this
by generating the efi binary directly from C code and removing the
architectural restrictions in the Makefile.am.  One of the
consequences of this is that we no longer test ia32 on x86_64, but the
difficulty of detecting which architectures can support 32 bit
variants and generating them correctly from EFI c code is too great.

We also need to exclude tests involving objdump from aarch64 since its
bfd still doesn't have an efi_app_aarch64 target.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

tests/test.c

@@ -0,0 +1,8 @@
+#include <efi.h>
+#include <efilib.h>
+
+EFI_STATUS
+efi_main (EFI_HANDLE image, EFI_SYSTEM_TABLE *systab)
+{
+	return EFI_SUCCESS;
+}