unfold UNREACHABLE implementation for dumb compilers

We relies on UNREACHABLE's noreturn attribute to eliminate parent's "no return value" warning. However, this was wrapped in a `if(!false)` block, which compilers may not unfold to recognize the noreturn nature.

src/common/assert.h

@@ -41,8 +41,8 @@ __declspec(noinline, noreturn)
         }                                                                                          \
     while (0)
 
-#define UNREACHABLE() ASSERT_MSG(false, "Unreachable code!")
-#define UNREACHABLE_MSG(...) ASSERT_MSG(false, __VA_ARGS__)
+#define UNREACHABLE() assert_noinline_call([] { LOG_CRITICAL(Debug, "Unreachable code!"); })
+#define UNREACHABLE_MSG(...) assert_noinline_call([] { LOG_CRITICAL(Debug, "Unreachable code!\n" __VA_ARGS__); })
 
 #ifdef _DEBUG
 #define DEBUG_ASSERT(_a_) ASSERT(_a_)