[llvm] [ThinLTO]Record import type (declaration or definition) in GlobalValueSummary::GVFlags (PR #87597)

[Mingming Liu via llvm-commits]

minglotus-6 wrote:

@teresajohnson I'm only updating one test case (llvm/test/Assembler/thinlto-summary.ll) to show how test cases are affected now. I'm planning to update the rest of test cases as review goes on (e.g., the name of field might change during review).

https://github.com/llvm/llvm-project/pull/87597