Rename mjit_gc_finish_hook to mjit_gc_exit_hook

because @ko1 said "gc_finish" is confusing like a finish of entire GC
process

gc.c

@@ -7140,7 +7140,7 @@ gc_exit(rb_objspace_t *objspace, const char *event)
     gc_report(1, objspace, "gc_exit: %s [%s]\n", event, gc_current_status(objspace));
     during_gc = FALSE;
 
-    mjit_gc_finish_hook();
+    mjit_gc_exit_hook();
 }
 
 static void *

mjit.c

@@ -99,15 +99,15 @@ mjit_gc_start_hook(void)
 // Send a signal to workers to continue iseq compilations.  It is
 // called at the end of GC.
 void
-mjit_gc_finish_hook(void)
+mjit_gc_exit_hook(void)
 {
     if (!mjit_enabled)
         return;
-    CRITICAL_SECTION_START(4, "mjit_gc_finish_hook");
+    CRITICAL_SECTION_START(4, "mjit_gc_exit_hook");
     in_gc = false;
     verbose(4, "Sending wakeup signal to workers after GC");
     rb_native_cond_broadcast(&mjit_gc_wakeup);
-    CRITICAL_SECTION_FINISH(4, "mjit_gc_finish_hook");
+    CRITICAL_SECTION_FINISH(4, "mjit_gc_exit_hook");
 }
 
 // Deal with ISeq movement from compactor

mjit.h

@@ -82,7 +82,7 @@ extern void mjit_init(struct mjit_options *opts);
 extern void mjit_postponed_job_register_start_hook(void);
 extern void mjit_postponed_job_register_finish_hook(void);
 extern void mjit_gc_start_hook(void);
-extern void mjit_gc_finish_hook(void);
+extern void mjit_gc_exit_hook(void);
 extern void mjit_free_iseq(const rb_iseq_t *iseq);
 extern void mjit_update_references(const rb_iseq_t *iseq);
 extern void mjit_mark(void);
@@ -167,7 +167,7 @@ static inline void mjit_cont_free(struct mjit_cont *cont){}
 static inline void mjit_postponed_job_register_start_hook(void){}
 static inline void mjit_postponed_job_register_finish_hook(void){}
 static inline void mjit_gc_start_hook(void){}
-static inline void mjit_gc_finish_hook(void){}
+static inline void mjit_gc_exit_hook(void){}
 static inline void mjit_free_iseq(const rb_iseq_t *iseq){}
 static inline void mjit_mark(void){}
 static inline void mjit_add_class_serial(rb_serial_t class_serial){}

mjit_worker.c

@@ -1052,7 +1052,7 @@ convert_unit_to_func(struct rb_mjit_unit *unit)
     // print #include of MJIT header, etc.
     compile_prelude(f);
 
-    // wait until mjit_gc_finish_hook is called
+    // wait until mjit_gc_exit_hook is called
     CRITICAL_SECTION_START(3, "before mjit_compile to wait GC finish");
     while (in_gc) {
         verbose(3, "Waiting wakeup from GC");