Remove unnecessary uses of AliasedSymbol.

As pr19627 points out, every use of AliasedSymbol is likely a bug.

The main use was to avoid the oddity of a variable showing up as undefined. That
was fixed in r233995, which made these calls nops.

llvm-svn: 234169
diff --git a/llvm/lib/MC/MCObjectWriter.cpp b/llvm/lib/MC/MCObjectWriter.cpp
index 33e4556..e40c07d 100644
--- a/llvm/lib/MC/MCObjectWriter.cpp
+++ b/llvm/lib/MC/MCObjectWriter.cpp
@@ -27,7 +27,7 @@
 
   const MCSymbol &SA = A->getSymbol();
   const MCSymbol &SB = B->getSymbol();
-  if (SA.AliasedSymbol().isUndefined() || SB.AliasedSymbol().isUndefined())
+  if (SA.isUndefined() || SB.isUndefined())
     return false;
 
   const MCSymbolData &DataA = Asm.getSymbolData(SA);
@@ -43,7 +43,7 @@
     const MCAssembler &Asm, const MCSymbolData &DataA,
     const MCSymbolData *DataB, const MCFragment &FB, bool InSet,
     bool IsPCRel) const {
-  const MCSection &SecA = DataA.getSymbol().AliasedSymbol().getSection();
+  const MCSection &SecA = DataA.getSymbol().getSection();
   const MCSection &SecB = FB.getParent()->getSection();
   // On ELF and COFF  A - B is absolute if A and B are in the same section.
   return &SecA == &SecB;