[llvm-reduce] Change initialization order to fix bots. NFC

Fixes this error:
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/
llvm-project/llvm/tools/llvm-reduce/TestRunner.cpp:20:7:
error: field 'TM' will be initialized after field 'ToolName'
[-Werror,-Wreorder-ctor]
      TM(std::move(TM)), ToolName(ToolName) {
      ^~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~~~~~~~
      Program(std::move(Program)) TM(std::move(TM))
1 error generated.

https://lab.llvm.org/buildbot/\#/builders/77/builds/19154