executor: move syz_execute_func after os imports. (#1107)

This commit moves the definition of the `syz_execute_func` after the
block of code that imports all the OS specific common headers.

This is required because after commit
dfd3394d42ddd333c68cf355273b312da8c65a51 `syz_execute_func` started
using the `NONFAILING` macro, which is defined in those header files for
each OS.

I also ran `make generate`.

TEST=I only tested that the executor works for Fuchsia with:

```shell
$ make executor TARGETOS=fuchsia TARGETARCH=amd64 SOURCEDIR=~/fuchsia
```

1 files changed, 16 insertions, 16 deletions

diff --git a/executor/common.h b/executor/common.h
index a0ed0026c..b6035eee1 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -379,6 +379,22 @@ static uint16 csum_inet_digest(struct csum_inet* csum)
 }
 #endif
 
+#if GOOS_akaros
+#include "common_akaros.h"
+#elif GOOS_freebsd || GOOS_netbsd || GOOS_openbsd
+#include "common_bsd.h"
+#elif GOOS_fuchsia
+#include "common_fuchsia.h"
+#elif GOOS_linux
+#include "common_linux.h"
+#elif GOOS_test
+#include "common_test.h"
+#elif GOOS_windows
+#include "common_windows.h"
+#else
+#error "unknown OS"
+#endif
+
 #if SYZ_EXECUTOR || __NR_syz_execute_func
 // syz_execute_func(text ptr[in, text[taget]])
 static long syz_execute_func(volatile long text)
@@ -400,22 +416,6 @@ static long syz_execute_func(volatile long text)
 }
 #endif
 
-#if GOOS_akaros
-#include "common_akaros.h"
-#elif GOOS_freebsd || GOOS_netbsd || GOOS_openbsd
-#include "common_bsd.h"
-#elif GOOS_fuchsia
-#include "common_fuchsia.h"
-#elif GOOS_linux
-#include "common_linux.h"
-#elif GOOS_test
-#include "common_test.h"
-#elif GOOS_windows
-#include "common_windows.h"
-#else
-#error "unknown OS"
-#endif
-
 #if SYZ_THREADED
 struct thread_t {
 	int created, call;