[test] Move cctest/test-thread-termination to unittests/

... execution/thread-termination-unittest.

Bug: v8:12781
Change-Id: I772ad8550e242eae66f76c5785aeb7f1e4425fae
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3688894
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81066}

test/cctest/BUILD.gn

@@ -216,7 +216,6 @@ v8_source_set("cctest_sources") {
     "test-swiss-name-dictionary-infra.cc",
     "test-swiss-name-dictionary.cc",
     "test-temporal-parser.cc",
-    "test-thread-termination.cc",
     "test-trace-event.cc",
     "test-transitions.cc",
     "test-transitions.h",

test/unittests/BUILD.gn

@@ -334,6 +334,7 @@ v8_source_set("unittests_sources") {
     "diagnostics/eh-frame-writer-unittest.cc",
     "diagnostics/gdb-jit-unittest.cc",
     "execution/microtask-queue-unittest.cc",
+    "execution/thread-termination-unittest.cc",
     "execution/threads-unittest.cc",
     "flags/flag-definitions-unittest.cc",
     "gay-fixed.cc",