8344074: RISC-V: C1: More accurate _exception_handler_size and _deopt_handler_size

Reviewed-by: mli, fjiang

Author: RealFYang

src/hotspot/cpu/riscv/c1_LIRAssembler_riscv.hpp

@@ -70,12 +70,11 @@ friend class ArrayCopyStub;
     _call_stub_size = 11 * MacroAssembler::instruction_size +
                       1 * MacroAssembler::instruction_size + wordSize,
     // See emit_exception_handler for detail
-    // verify_not_null_oop + far_call + should_not_reach_here + invalidate_registers(DEBUG_ONLY)
-    _exception_handler_size = DEBUG_ONLY(584) NOT_DEBUG(548), // or smaller
+    _exception_handler_size = DEBUG_ONLY(256) NOT_DEBUG(32), // or smaller
     // See emit_deopt_handler for detail
-    // auipc (1) + far_jump (6 or 2)
+    // auipc (1) + far_jump (2)
     _deopt_handler_size = 1 * MacroAssembler::instruction_size +
-                          6 * MacroAssembler::instruction_size // or smaller
+                          2 * MacroAssembler::instruction_size
   };
 
   void check_conflict(ciKlass* exact_klass, intptr_t current_klass, Register tmp,