[Backport to llvm_release_190] Add missing includes to headers (KhronosGroup#3435)

Backport of PR KhronosGroup#3413 into `llvm_release_190`.

All commits applied cleanly.

Co-authored-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

Author: github-actions[bot]

include/LLVMSPIRVLib.h

@@ -43,8 +43,11 @@
 
 #include "LLVMSPIRVOpts.h"
 
+#include <cstdint>
 #include <iostream>
+#include <optional>
 #include <string>
+#include <vector>
 
 namespace llvm {
 // Pass initialization functions need to be declared before inclusion of

include/LLVMSPIRVOpts.h

@@ -47,6 +47,7 @@
 #include <map>
 #include <optional>
 #include <unordered_map>
+#include <vector>
 
 namespace llvm {
 class IntrinsicInst;