RISC-V: Enable fast class initialization checks

I note that linux-riscv64 doesn't enable fast_class_init by default. It seems that the reason is we are lacking following code change for this platform:

```

diff --git a/src/hotspot/cpu/riscv/vm_version_riscv.hpp b/src/hotspot/cpu/riscv/vm_version_riscv.hpp
index 3c769ebfe2a..c0737996106 100644
--- a/src/hotspot/cpu/riscv/vm_version_riscv.hpp
+++ b/src/hotspot/cpu/riscv/vm_version_riscv.hpp
@@ -205,6 +205,8 @@ class VM_Version : public Abstract_VM_Version {
   static void initialize();
   static void initialize_cpu_information();
 
+  static bool supports_fast_class_init_checks() { return true; }
+
   constexpr static bool supports_stack_watermark_barrier() { return true; }
 
   static bool supports_on_spin_wait() { return UseZihintpause; }

```