[SampleFDO] Add missing #includes to unbreak modules build after D96455

Bot: http://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/28999

```
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h:124:19: error: missing '#include "llvm/Analysis/PostDominators.h"'; 'PostDominatorTree' must be declared before it is used
  std::unique_ptr<PostDominatorTree> PDT;
                  ^
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Analysis/PostDominators.h:28:7: note: declaration here is not visible
class PostDominatorTree : public PostDomTreeBase<BasicBlock> {
      ^
While building module 'LLVM_Transforms' imported from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/Transforms/CFGuard/CFGuard.cpp:15:
In file included from <module-includes>:191:
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h:125:19: error: missing '#include "llvm/Analysis/LoopInfo.h"'; 'LoopInfo' must be declared before it is used
  std::unique_ptr<LoopInfo> LI;
                  ^
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Analysis/LoopInfo.h:1079:7: note: declaration here is not visible
class LoopInfo : public LoopInfoBase<BasicBlock, Loop> {
      ^
While building module 'LLVM_Transforms' imported from /Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/Transforms/CFGuard/CFGuard.cpp:15:
In file included from <module-includes>:191:
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h:149:3: error: missing '#include "llvm/Analysis/OptimizationRemarkEmitter.h"'; 'OptimizationRemarkEmitter' must be declared before it is used
  OptimizationRemarkEmitter *ORE = nullptr;
  ^
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/Analysis/OptimizationRemarkEmitter.h:33:7: note: declaration here is not visible
class OptimizationRemarkEmitter {
      ^
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/lib/Transforms/CFGuard/CFGuard.cpp:15:10: fatal error: could not build module 'LLVM_Transforms'
```

Author: vedantk

llvm/include/llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h

@@ -21,6 +21,9 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/Analysis/PostDominators.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/DebugInfoMetadata.h"