CodeLoader: Mark GetStackPointer() as const

This isn't intended to modify anything.

Source/Tools/CommonTools/CodeLoader.h

@@ -30,7 +30,7 @@ public:
   /**
    * Returns the initial stack pointer
    */
-  virtual uint64_t GetStackPointer() = 0;
+  virtual uint64_t GetStackPointer() const = 0;
 
   /**
    * @brief Function to return the guest RIP that the code should start out at

Source/Tools/CommonTools/HarnessHelpers.h

@@ -453,7 +453,7 @@ public:
     return Page > 0 ? Page : FEXCore::Utils::FEX_PAGE_SIZE;
   }
 
-  uint64_t GetStackPointer() override {
+  uint64_t GetStackPointer() const override {
     LOGMAN_MSG_A_FMT("This should be unused.");
     FEX_UNREACHABLE;
   }

Source/Tools/FEXLoader/ELFCodeLoader.h

@@ -354,15 +354,15 @@ public:
     Sections.clear();
   }
 
-  virtual uint64_t StackSize() const override {
+  uint64_t StackSize() const override {
     return STACK_SIZE;
   }
-  virtual uint64_t GetStackPointer() override {
+  uint64_t GetStackPointer() const override {
     return StackPointer;
   }
-  virtual uint64_t DefaultRIP() const override {
+  uint64_t DefaultRIP() const override {
     return Entrypoint;
-  };
+  }
 
   struct auxv32_t {
     uint32_t key;