[EXPORTER] General cleanup for is_shutdown_ flags in exporters. #9587

Job	Run time
CMake clang 15 (maintainer mode, abiv2)	13m 50s
CMake clang 15 (maintainer mode, async)	14m 48s
CMake clang 15 (maintainer mode, sync)	15m 4s
CMake gcc 13 (maintainer mode, async)	7m 20s
CMake gcc 13 (maintainer mode, sync)	6m 59s
CMake test (without otlp-exporter)	4m 37s
CMake test (with abseil)	4m 59s
CMake msvc (maintainer mode)	6m 52s
CMake msvc (maintainer mode) with C++20	7m 30s
CMake test (with opentracing-shim)	4m 11s
CMake C++14 test(GCC)	3m 59s
CMake C++17 test(GCC)	4m 32s
CMake test (without otlp-exporter and with async export)	4m 51s
Bazel	13m 39s
CMake do not install test (with otlp-exporter)	14m 31s
CMake install test (with abseil)	4m 37s
CMake test (with modern protobuf,grpc and abseil)	18m 18s
CMake test (build shared libraries with otlp-exporter and static gRPC)	13m 27s
CMake test (with otlp-exporter)	14m 20s
CMake C++20 test(Clang with libc++)	9m 6s
CMake C++20 test(GCC)	8m 24s
CMake C++23 test(Clang with libc++)	9m 10s
CMake C++23 test(GCC)	8m 17s
Plugin -> CMake	1m 0s
Bazel asan config	15m 5s
Bazel noexcept	12m 23s
Bazel nortti	12m 53s
Bazel on MacOS	10m 11s
Bazel with async export	12m 57s
Bazel tsan config	13m 48s
Bazel valgrind	14m 35s
Bazel with external abseil	13m 18s
Benchmark	8m 51s
Copyright	5s
Format	13s
Code coverage	11m 27s
DocFX check	1m 1s
markdown-lint	9s
misspell	4s
shellcheck	5s
CMake -> exporter proto	11m 56s
Bazel Windows	18m 35s
Plugin -> CMake Windows	6m 6s
CMake (With async export) -> exporter proto	12m 8s
CMake -> exporter proto (Build as DLL)	25m 57s
	6h 56m 8s

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