Added source location for the template keyword in DependentTemplateSpecializationTypeLoc nodes (DTSTLoc).

The new info is propagated to TSTLoc on template instantiation, getting rid of 3 FIXMEs in TreeTransform.h and another one Parser.cpp.

Simplified code in TypeSpecLocFiller visitor methods for DTSTLoc and DependentNameTypeLoc by removing what now seems to be dead code (adding corresponding assertions). 

llvm-svn: 149923
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 64ffb15..1d19312 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -4345,6 +4345,7 @@
        DependentTemplateSpecializationTypeLoc TL) {
   TL.setElaboratedKeywordLoc(ReadSourceLocation(Record, Idx));
   TL.setQualifierLoc(Reader.ReadNestedNameSpecifierLoc(F, Record, Idx));
+  TL.setTemplateKeywordLoc(ReadSourceLocation(Record, Idx));
   TL.setTemplateNameLoc(ReadSourceLocation(Record, Idx));
   TL.setLAngleLoc(ReadSourceLocation(Record, Idx));
   TL.setRAngleLoc(ReadSourceLocation(Record, Idx));