YJIT: reduce default --yjit-exec-mem-size to 128MiB instead of 256 (ruby#6649)

Reduce default --yjit-exec-mem-size to 128MiB instead of 256

Author: Maxime Chevalier-Boisvert

yjit/src/options.rs

@@ -53,7 +53,7 @@ pub struct Options {
 
 // Initialize the options to default values
 pub static mut OPTIONS: Options = Options {
-    exec_mem_size: 256 * 1024 * 1024,
+    exec_mem_size: 128 * 1024 * 1024,
     code_page_size: 16 * 1024,
     call_threshold: 10,
     greedy_versioning: false,