Add Starboard thread_sampler APIs to Android (#2689)

Swaps Starboard's thread_sampler APIs for Android TV from stub to shared
implementations (`//starboard/shared/stub/thread_sampler_*` to
`//starboard/shared/pthread/thread_sampler_*`).

Tested on Android TV (x64), Google TV Emulator (arm64), and a real
Google TV device (arm).

Test-On-Device: true

b/330564529

Co-authored-by: Ahmed Elzeiny <[email protected]>
(cherry picked from commit 7984c7a)

starboard/android/shared/BUILD.gn

@@ -166,6 +166,9 @@ static_library("starboard_platform") {
     "//starboard/shared/pthread/mutex_destroy.cc",
     "//starboard/shared/pthread/mutex_release.cc",
     "//starboard/shared/pthread/once.cc",
+    "//starboard/shared/pthread/thread_context_get_pointer.cc",
+    "//starboard/shared/pthread/thread_context_internal.cc",
+    "//starboard/shared/pthread/thread_context_internal.h",
     "//starboard/shared/pthread/thread_create_local_key.cc",
     "//starboard/shared/pthread/thread_create_priority.h",
     "//starboard/shared/pthread/thread_destroy_local_key.cc",
@@ -174,6 +177,13 @@ static_library("starboard_platform") {
     "//starboard/shared/pthread/thread_get_local_value.cc",
     "//starboard/shared/pthread/thread_is_equal.cc",
     "//starboard/shared/pthread/thread_join.cc",
+    "//starboard/shared/pthread/thread_sampler_create.cc",
+    "//starboard/shared/pthread/thread_sampler_destroy.cc",
+    "//starboard/shared/pthread/thread_sampler_freeze.cc",
+    "//starboard/shared/pthread/thread_sampler_internal.cc",
+    "//starboard/shared/pthread/thread_sampler_internal.h",
+    "//starboard/shared/pthread/thread_sampler_is_supported.cc",
+    "//starboard/shared/pthread/thread_sampler_thaw.cc",
     "//starboard/shared/pthread/thread_set_local_value.cc",
     "//starboard/shared/pthread/thread_yield.cc",
     "//starboard/shared/signal/crash_signals.h",
@@ -250,12 +260,6 @@ static_library("starboard_platform") {
     "//starboard/shared/stub/system_request_focus.cc",
     "//starboard/shared/stub/system_request_reveal.cc",
     "//starboard/shared/stub/system_sign_with_certification_secret_key.cc",
-    "//starboard/shared/stub/thread_context_get_pointer.cc",
-    "//starboard/shared/stub/thread_sampler_create.cc",
-    "//starboard/shared/stub/thread_sampler_destroy.cc",
-    "//starboard/shared/stub/thread_sampler_freeze.cc",
-    "//starboard/shared/stub/thread_sampler_is_supported.cc",
-    "//starboard/shared/stub/thread_sampler_thaw.cc",
     "//starboard/shared/stub/ui_nav_get_interface.cc",
     "accessibility_get_caption_settings.cc",
     "accessibility_get_display_settings.cc",