[Object] Fix the return type of getOffset/getSize

Header64.offset/Header64.size are uint64_t, thus we should not 
truncate them to unit32_t. Moreover, there are a number of places 
where we sum the offset and the size (e.g. in various checks in MachOUniversal.cpp),
the truncation causes issues since the offset/size can perfectly fit into uint32_t, 
while the sum overflows.

Differential revision: https://reviews.llvm.org/D69126

Test plan: make check-all

llvm-svn: 375154

Author: alexander-shaposhnikov

llvm/include/llvm/Object/MachOUniversal.h

@@ -66,13 +66,13 @@ class MachOUniversalBinary : public Binary {
       else // Parent->getMagic() == MachO::FAT_MAGIC_64
         return Header64.cpusubtype;
     }
-    uint32_t getOffset() const {
+    uint64_t getOffset() const {
       if (Parent->getMagic() == MachO::FAT_MAGIC)
         return Header.offset;
       else // Parent->getMagic() == MachO::FAT_MAGIC_64
         return Header64.offset;
     }
-    uint32_t getSize() const {
+    uint64_t getSize() const {
       if (Parent->getMagic() == MachO::FAT_MAGIC)
         return Header.size;
       else // Parent->getMagic() == MachO::FAT_MAGIC_64