Dynarmic Interface: don't clear cache if JIT has not been created.

src/core/arm/dynarmic/arm_dynarmic_32.cpp

@@ -200,6 +200,9 @@ void ARM_Dynarmic_32::PrepareReschedule() {
 }
 
 void ARM_Dynarmic_32::ClearInstructionCache() {
+    if (!jit) {
+        return;
+    }
     jit->ClearCache();
 }
 

src/core/arm/dynarmic/arm_dynarmic_64.cpp

@@ -301,6 +301,9 @@ void ARM_Dynarmic_64::PrepareReschedule() {
 }
 
 void ARM_Dynarmic_64::ClearInstructionCache() {
+    if (!jit) {
+        return;
+    }
     jit->ClearCache();
 }