Rename alloca_overflow to stack_overflow

`alloca` is an implementation detail to raise a stack overflow.

Author: nobu

ext/-test-/stack/stack.c

@@ -2,7 +2,7 @@
 #include "internal/string.h"
 
 static VALUE
-stack_alloca_overflow(VALUE self)
+stack_overflow(VALUE self)
 {
     size_t i = 0;
 
@@ -30,6 +30,6 @@ asan_p(VALUE klass)
 void
 Init_stack(VALUE klass)
 {
-    rb_define_singleton_method(rb_cThread, "alloca_overflow", stack_alloca_overflow, 0);
+    rb_define_singleton_method(rb_cThread, "stack_overflow", stack_overflow, 0);
     rb_define_singleton_method(rb_cThread, "asan?", asan_p, 0);
 }

test/-ext-/stack/test_stack_overflow.rb

@@ -17,7 +17,7 @@ def test_overflow
       require '-test-/stack'
 
       assert_raise(SystemStackError) do
-        Thread.alloca_overflow
+        Thread.stack_overflow
       end
     RUBY
   end
@@ -29,7 +29,7 @@ def test_thread_stack_overflow
 
       thread = Thread.new do
         Thread.current.report_on_exception = false
-        Thread.alloca_overflow
+        Thread.stack_overflow
       end
 
       assert_raise(SystemStackError) do
@@ -44,7 +44,7 @@ def test_fiber_stack_overflow
       GC.disable
 
       fiber = Fiber.new do
-        Thread.alloca_overflow
+        Thread.stack_overflow
       end
 
       assert_raise(SystemStackError) do