Make sure pal_icushim_static.c is linked in even if no symbols are used from...

Make sure pal_icushim_static.c is linked in even if no symbols are used from it, so the EMSCRIPTEN_KEEPALIVE functions in it are actually kept. (#48550)

src/libraries/Native/Unix/System.Globalization.Native/pal_icushim_static.c

@@ -88,6 +88,16 @@ EMSCRIPTEN_KEEPALIVE int32_t mono_wasm_load_icu_data(void * pData)
         return 1;
     }
 }
+
+/*
+ * driver.c calls this to make sure this file is linked, otherwise
+ * its not, meaning the EMSCRIPTEN_KEEPALIVE functions above
+ * are not kept.
+ */
+void mono_wasm_link_icu_shim(void)
+{
+}
+
 #endif
 
 int32_t GlobalizationNative_LoadICU(void)

src/mono/wasm/runtime/driver.c

@@ -466,11 +466,15 @@ mono_wasm_register_bundled_satellite_assemblies ()
 	}
 }
 
+void mono_wasm_link_icu_shim (void);
+
 EMSCRIPTEN_KEEPALIVE void
 mono_wasm_load_runtime (const char *unused, int debug_level)
 {
 	const char *interp_opts = "";
 
+	mono_wasm_link_icu_shim ();
+
 #ifdef DEBUG
 	monoeg_g_setenv ("MONO_LOG_LEVEL", "debug", 0);
 	monoeg_g_setenv ("MONO_LOG_MASK", "gc", 0);