Include ruby/ruby.h before vm_core.h

This is how vm.c does it, and if we don't follow it in yjit
compilation units, rb_vm_t would have a conflicting size.

yjit_core.c

@@ -1,14 +1,10 @@
-#include "vm_core.h"
-#include "vm_callinfo.h"
-#include "builtin.h"
-#include "insns.inc"
-#include "insns_info.inc"
-#include "vm_sync.h"
 #include "yjit_asm.h"
 #include "yjit_utils.h"
 #include "yjit_iface.h"
 #include "yjit_core.h"
 #include "yjit_codegen.h"
+#include "vm_sync.h"
+#include "builtin.h"
 
 // Maximum number of versions per block
 #define MAX_VERSIONS 4

yjit_iface.c

@@ -1,7 +1,7 @@
-#include <assert.h>
+#include "ruby/ruby.h"
+#include "vm_core.h"
 #include "insns.inc"
 #include "internal.h"
-#include "vm_core.h"
 #include "vm_sync.h"
 #include "vm_callinfo.h"
 #include "builtin.h"

yjit_iface.h

@@ -6,21 +6,10 @@
 #ifndef YJIT_IFACE_H
 #define YJIT_IFACE_H 1
 
-#include "stddef.h"
-#include "stdint.h"
-#include "stdbool.h"
-#include "internal.h"
-#include "ruby/internal/attr/nodiscard.h"
+#include "ruby/ruby.h"
 #include "vm_core.h"
-#include "vm_callinfo.h"
-#include "builtin.h"
 #include "yjit_core.h"
 
-#ifndef rb_callcache
-struct rb_callcache;
-#define rb_callcache rb_callcache
-#endif
-
 #define YJIT_DECLARE_COUNTERS(...) struct rb_yjit_runtime_counters { \
     int64_t __VA_ARGS__; \
 }; \