test: fix the unit test fail issue under single_core config

Introduced in 97e3542947.

The previous commit frees the IRAM part when single core, but doesn't
change the memory layout functions. The unit test mallocs IRAM memory
from the heap, accidently into the new-released region, which doesn't
match the memory layout function.

This commit update the memory layout function to fix this.

components/soc/include/soc/soc_memory_layout.h

@@ -175,7 +175,11 @@ inline static bool IRAM_ATTR esp_ptr_external_ram(const void *p) {
 }
 
 inline static bool IRAM_ATTR esp_ptr_in_iram(const void *p) {
+#ifndef CONFIG_FREERTOS_UNICORE
     return ((intptr_t)p >= SOC_IRAM_LOW && (intptr_t)p < SOC_IRAM_HIGH);
+#else
+    return ((intptr_t)p >= SOC_CACHE_APP_LOW && (intptr_t)p < SOC_IRAM_HIGH);
+#endif
 }
 
 inline static bool IRAM_ATTR esp_ptr_in_drom(const void *p) {