CPU/CodeCache: Dynamically compute BIOS memory access timing

The timings can change if the game does so. Instead of forcing the
blocks to recompile, we can just manually multiply size * word_time.

Improves stability of Nightmare Creatures booting, and fixes corrupted
text in Formula Circus when using the cached interpreter.

src/core/cpu_code_cache_private.h

@@ -94,6 +94,8 @@ enum class BlockFlags : u8
   ContainsLoadStoreInstructions = (1 << 0),
   SpansPages = (1 << 1),
   BranchDelaySpansPages = (1 << 2),
+  IsUsingICache = (1 << 3),
+  NeedsDynamicFetchTicks = (1 << 4),
 };
 IMPLEMENT_ENUM_CLASS_BITWISE_OPERATORS(BlockFlags);