[BOLT] Fix bolt_info ELF note

Summary:
Small fix - align the end of the descriptor string as well,
since readelf will detect when it is not aligned and print an error
instead of printing BOLT version and command line.

(cherry picked from FBD6023643)

Author: rafaelauler

bolt/RewriteInstance.cpp

@@ -3056,17 +3056,21 @@ void RewriteInstance::addBoltInfoSection() {
     raw_string_ostream OS(Str);
     std::string NameStr = "GNU";
     const uint32_t NameSz = NameStr.size() + 1;
-    const uint32_t DescSz = DescStr.size() + 1;
+    const uint32_t DescSz = DescStr.size();
     const uint32_t Type = 4; // NT_GNU_GOLD_VERSION (gold version)
     OS.write(reinterpret_cast<const char*>(&(NameSz)), 4);
     OS.write(reinterpret_cast<const char*>(&(DescSz)), 4);
     OS.write(reinterpret_cast<const char*>(&(Type)), 4);
-    OS << NameStr << '\0';
-    for (uint64_t I = NameStr.size() + 1;
-         I < RoundUpToAlignment(NameStr.size() + 1, 4); ++I) {
+    OS << NameStr;
+    for (uint64_t I = NameStr.size();
+         I < RoundUpToAlignment(NameStr.size(), 4); ++I) {
+      OS << '\0';
+    }
+    OS << DescStr;
+    for (uint64_t I = DescStr.size();
+         I < RoundUpToAlignment(DescStr.size(), 4); ++I) {
       OS << '\0';
     }
-    OS << DescStr << '\0';
 
     const auto BoltInfo = OS.str();
     const auto SectionSize = BoltInfo.size();