[MC] Remove a stray space after tab for COFF .def directives

[mstorsjo]

Summary

This extra stray space after tab can be traced back to when printing
of this directive was added originally in
4f01b783a3ca5b2544fe1b1677b5bcf6d91c6d2c. The same commit added
inconsistent printing of space after the ELF .type directive too,
which was fixed later in
77fe07a93aeb8feaf39b7d48ad8fc1e6c9e4c78e.

(This is kind of NFC, but it does alter the output, so it's not
strictly non-functional in that sense.)

[asl]

Neat! :)

[rnk]

lgtm

llvm/lib/MC/MCAsmStreamer.cpp

if (MAI->getAssemblerDialect() == 1) {
     EmitEOL();
   }
   // FIXME: Currently emit unprefix'ed registers.
   // The intel_syntax directive has one optional argument
   // with may have a value of prefix or noprefix.
 }
 
 void MCAsmStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
-  OS << "\t.def\t ";
+  OS << "\t.def\t";
   Symbol->print(OS, MAI);
   OS << ';';
   EmitEOL();
 }
 
 void MCAsmStreamer::EmitCOFFSymbolStorageClass (int StorageClass) {
   OS << "\t.scl\t" << StorageClass << ';';
   EmitEOL();