chore: place init_flash after init_core

First, this does not introduce any functional changes.

Second, the reason for this modification is that with the
introduction of OpenXiangShan/XiangShan#4626,
the simulation output includes some less elegant messages:

Using simulated 32768B flash
Core  0's Commit SHA is: 6683fc49ec, dirty: 1
Using simulated 8386560MB RAM

This change makes the output look better.

Author: NewPaulWalker

src/test/csrc/verilator/emu.cpp

@@ -377,8 +377,6 @@ Emulator::Emulator(int argc, const char *argv[])
   if (enable_simjtag) {
     jtag_init();
   }
-  // init flash
-  init_flash(args.flash_bin);
 
 #if VM_TRACE == 1
   if (args.enable_waveform) {
@@ -401,6 +399,9 @@ Emulator::Emulator(int argc, const char *argv[])
   // init core
   reset_ncycles(args.reset_cycles);
 
+  // init flash
+  init_flash(args.flash_bin);
+
   // init ram
   uint64_t ram_size = DEFAULT_EMU_RAM_SIZE;
   if (args.ram_size) {