tests/tcg: move i386 specific tests into subdir

These only need to be built for i386 guests. This includes a stub
tests/tcg/i386/Makfile.target which absorbs some of what was in
tests/tcg/Makefile.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

tests/tcg/i386/test-i386-code16.S

@@ -0,0 +1,79 @@
+        .code16
+        .globl code16_start
+        .globl code16_end
+
+CS_SEG = 0xf
+
+code16_start:
+
+        .globl code16_func1
+
+        /* basic test */
+code16_func1 = . - code16_start
+        mov $1, %eax
+        data32 lret
+
+/* test push/pop in 16 bit mode */
+        .globl code16_func2
+code16_func2 = . - code16_start
+        xor %eax, %eax
+        mov $0x12345678, %ebx
+        movl %esp, %ecx
+        push %bx
+        subl %esp, %ecx
+        pop %ax
+        data32 lret
+
+/* test various jmp opcodes */
+        .globl code16_func3
+code16_func3 = . - code16_start
+        jmp 1f
+        nop
+1:
+        mov $4, %eax
+        mov $0x12345678, %ebx
+        xor %bx, %bx
+        jz 2f
+        add $2, %ax
+2:
+
+        call myfunc
+
+        lcall $CS_SEG, $(myfunc2 - code16_start)
+
+        ljmp $CS_SEG, $(myjmp1 - code16_start)
+myjmp1_next:
+
+        cs lcall *myfunc2_addr - code16_start
+
+        cs ljmp *myjmp2_addr - code16_start
+myjmp2_next:
+
+        data32 lret
+
+myfunc2_addr:
+        .short myfunc2 - code16_start
+        .short CS_SEG
+
+myjmp2_addr:
+        .short myjmp2 - code16_start
+        .short CS_SEG
+
+myjmp1:
+        add $8, %ax
+        jmp myjmp1_next
+
+myjmp2:
+        add $16, %ax
+        jmp myjmp2_next
+
+myfunc:
+        add $1, %ax
+        ret
+
+myfunc2:
+        add $4, %ax
+        lret
+
+
+code16_end: