[clang] Fix GCC -Wparentheses warning. NFC.

Without this gcc warned like:
clang/lib/Sema/SemaExprCXX.cpp:4656:74: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
 4655 |              From->isNullPointerConstant(Context,
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 4656 |                                          Expr::NPC_ValueDependentIsNull) &&
      |                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
 4657 |                  "Expr must be null pointer constant!");
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Author: ChunyuLiao

clang/lib/Sema/SemaExprCXX.cpp

@@ -4651,9 +4651,9 @@ Sema::PerformImplicitConversion(Expr *From, QualType ToType,
         From->getExprLoc(), From->getSourceRange(), CStyle,
         MemberPointerConversionDirection::Downcast)) {
     case MemberPointerConversionResult::Success:
-      assert(Kind != CK_NullToMemberPointer ||
+      assert((Kind != CK_NullToMemberPointer ||
              From->isNullPointerConstant(Context,
-                                         Expr::NPC_ValueDependentIsNull) &&
+                                         Expr::NPC_ValueDependentIsNull)) &&
                  "Expr must be null pointer constant!");
       break;
     case MemberPointerConversionResult::Inaccessible: