[clang][AST] Make some ASTContext functions static (#163921)

They don't use the instance at all, so make them static.

Author: tbaederr

clang/include/clang/AST/ASTContext.h

@@ -2874,11 +2874,11 @@ class ASTContext : public RefCountedBase<ASTContext> {
   /// returned type is guaranteed to be free of any of these, allowing two
   /// canonical types to be compared for exact equality with a simple pointer
   /// comparison.
-  CanQualType getCanonicalType(QualType T) const {
+  static CanQualType getCanonicalType(QualType T) {
     return CanQualType::CreateUnsafe(T.getCanonicalType());
   }
 
-  const Type *getCanonicalType(const Type *T) const {
+  static const Type *getCanonicalType(const Type *T) {
     return T->getCanonicalTypeInternal().getTypePtr();
   }
 
@@ -2890,10 +2890,10 @@ class ASTContext : public RefCountedBase<ASTContext> {
   CanQualType getCanonicalParamType(QualType T) const;
 
   /// Determine whether the given types \p T1 and \p T2 are equivalent.
-  bool hasSameType(QualType T1, QualType T2) const {
+  static bool hasSameType(QualType T1, QualType T2) {
     return getCanonicalType(T1) == getCanonicalType(T2);
   }
-  bool hasSameType(const Type *T1, const Type *T2) const {
+  static bool hasSameType(const Type *T1, const Type *T2) {
     return getCanonicalType(T1) == getCanonicalType(T2);
   }
 
@@ -2921,7 +2921,7 @@ class ASTContext : public RefCountedBase<ASTContext> {
 
   /// Determine whether the given types are equivalent after
   /// cvr-qualifiers have been removed.
-  bool hasSameUnqualifiedType(QualType T1, QualType T2) const {
+  static bool hasSameUnqualifiedType(QualType T1, QualType T2) {
     return getCanonicalType(T1).getTypePtr() ==
            getCanonicalType(T2).getTypePtr();
   }