Initialize class fields to null/zero

Silence a couple of static analyzer warnings.

FEXCore/Source/Interface/IR/Passes/x87StackOptimizationPass.cpp

@@ -345,7 +345,7 @@ private:
   bool SlowPath = false;
   // Keeping IREmitter not to pass arguments around
   IREmitter* IREmit = nullptr;
-  IRListView* IR;
+  IRListView* IR = nullptr;
 };
 
 inline void X87StackOptimization::InvalidateCaches() {

Source/Tools/LinuxEmulation/LinuxSyscalls/x32/Types.h

@@ -1343,6 +1343,9 @@ struct shmid_ds_32 {
     shm_cpid = buf.shm_cpid;
     shm_lpid = buf.shm_lpid;
     shm_nattch = buf.shm_nattch;
+    shm_unused = 0;
+    shm_unused2 = 0;
+    shm_unused3 = 0;
   }
 };