The fragment implies the section, don't store both.

This reduces MCSymbol from 64 to 56 bytes on x86_64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238747 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCSymbol.cpp

@@ -42,7 +42,8 @@ void MCSymbol::setVariableValue(const MCExpr *Value) {
   assert(!IsUsed && "Cannot set a variable that has already been used.");
   assert(Value && "Invalid variable value!");
   this->Value = Value;
-  this->Section = nullptr;
+  Section = nullptr;
+  HasFragment = false;
 }
 
 void MCSymbol::print(raw_ostream &OS) const {