Use new aws_byte_buf_init_from_file_with_size_hint() function, so don…

…'t waste 4KB on these short strings.

source/linux/system_info.c

@@ -6,10 +6,14 @@
 #include <aws/common/private/system_info_priv.h>
 
 int aws_system_environment_load_platform_impl(struct aws_system_environment *env) {
-    aws_byte_buf_init_from_file(&env->virtualization_vendor, env->allocator, "/sys/devices/virtual/dmi/id/sys_vendor");
+    /* provide size_hint when reading "special files", since some platforms mis-report these files' size as 4KB */
+    aws_byte_buf_init_from_file_with_size_hint(
+        &env->virtualization_vendor, env->allocator, "/sys/devices/virtual/dmi/id/sys_vendor", 32 /*size_hint*/);
+
     /* whether this one works depends on if this is a sysfs filesystem. If it fails, it will just be empty
      * and these APIs are a best effort at the moment. We can add fallbacks as the loaders get more complicated. */
-    aws_byte_buf_init_from_file(&env->product_name, env->allocator, "/sys/devices/virtual/dmi/id/product_name");
+    aws_byte_buf_init_from_file_with_size_hint(
+        &env->product_name, env->allocator, "/sys/devices/virtual/dmi/id/product_name", 32 /*size_hint*/);
 
     return AWS_OP_SUCCESS;
 }