[BOLT] Fix crash for relocs in data sections against ABS symbols (#76026)

Fixes #75771

Author: mtvec

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -2524,7 +2524,7 @@ void RewriteInstance::handleRelocation(const SectionRef &RelocatedSection,
       Expected<StringRef> SectionName = Section->getName();
       if (SectionName && !SectionName->empty())
         ReferencedSection = BC->getUniqueSectionByName(*SectionName);
-    } else if (ReferencedSymbol &&
+    } else if (ReferencedSymbol && ContainingBF &&
                (cantFail(Symbol.getFlags()) & SymbolRef::SF_Absolute)) {
       // This might be a relocation for an ABS symbols like __global_pointer$ on
       // RISC-V