Fix 5a88027: [Script] Avoid overflow in scripts when infinite money is enabled (#12016)

src/script/api/script_company.cpp

@@ -178,6 +178,8 @@
 {
 	company = ResolveCompanyID(company);
 	if (company == COMPANY_INVALID) return -1;
+	/* If we return INT64_MAX as usual, overflows may occur in the script. So return a smaller value. */
+	if (_settings_game.difficulty.infinite_money) return INT32_MAX;
 
 	return GetAvailableMoney((::CompanyID)company);
 }

src/script/api/script_company.hpp

@@ -258,9 +258,10 @@ public:
 
 	/**
 	 * Gets the bank balance. In other words, the amount of money the given company can spent.
+	 * If infinite money is enabled, it returns INT32_MAX.
 	 * @param company The company to get the bank balance of.
 	 * @pre ResolveCompanyID(company) != COMPANY_INVALID.
-	 * @return The actual bank balance.
+	 * @return The actual bank balance or INT32_MAX.
 	 */
 	static Money GetBankBalance(CompanyID company);