[Coverity][XPTI] Unnecessary copies/copy instead of move

[AlexeySachkov]

See Coverity issues at https://scan.coverity.com/projects/intel-llvm?tab=overview

CID 440843, unnecessary copy with auto instead of auto &

llvm/xptifw/src/xpti_trace_framework.cpp

Line 1482 in d5c284d

auto Tmp = StreamCBs[TraceType];

CID 436649, copy instead of move

llvm/xptifw/include/xpti_string_table.hpp

Lines 66 to 67 in d5c284d

	std::string LocalStr = str;
	return add(LocalStr, ref_str);

CID 443079, copy instead of move

llvm/xptifw/src/xpti_trace_framework.cpp

Line 446 in d5c284d

MHandleLUT[Handle] = Data;