.*: Replace spurious gtest.h includes

Attempting to include gtest.h in a unit test using the "light" backend
to pw_unit_test will no longer work in Bazel after the backend is tidied
up.

Bug: 390709187
Change-Id: Ie5439c3a184564a7947ad56521b8615eaa71244a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/266972
Pigweed-Auto-Submit: Ted Pudlik <tpudlik@google.com>
Docs-Not-Needed: Ted Pudlik <tpudlik@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>

pw_build/linker_symbol_test.cc

@@ -14,7 +14,7 @@
 
 #include "pw_build/linker_symbol.h"
 
-#include "gtest/gtest.h"
+#include "pw_unit_test/framework.h"
 
 namespace pw {
 namespace {

pw_channel/epoll_channel_test.cc

@@ -19,7 +19,6 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include "gtest/gtest.h"
 #include "pw_assert/check.h"
 #include "pw_async2/dispatcher.h"
 #include "pw_bytes/array.h"
@@ -30,6 +29,7 @@
 #include "pw_thread/sleep.h"
 #include "pw_thread/thread.h"
 #include "pw_thread_stl/options.h"
+#include "pw_unit_test/framework.h"
 
 namespace {
 

pw_display/color_test.cc

@@ -14,9 +14,9 @@
 
 #include "pw_display/color.h"
 
-#include "gtest/gtest.h"
 #include "pw_display/colors_endesga64.h"
 #include "pw_display/colors_pico8.h"
+#include "pw_unit_test/framework.h"
 
 namespace pw::display {
 namespace {

pw_uart/stream_test.cc

@@ -14,7 +14,7 @@
 
 #include "pw_uart/stream.h"
 
-#include "gtest/gtest.h"
+#include "pw_unit_test/framework.h"
 
 namespace pw::uart {
 namespace {

pw_uart/uart_non_blocking_test.cc

@@ -16,11 +16,11 @@
 
 #include <cstdint>
 
-#include "gtest/gtest.h"
 #include "pw_bytes/span.h"
 #include "pw_function/function.h"
 #include "pw_status/status.h"
 #include "pw_status/status_with_size.h"
+#include "pw_unit_test/framework.h"
 
 namespace pw::uart {
 namespace {

pw_uart/uart_test.cc

@@ -14,9 +14,9 @@
 
 #include "pw_uart/uart.h"
 
-#include "gtest/gtest.h"
 #include "pw_status/status.h"
 #include "pw_status/status_with_size.h"
+#include "pw_unit_test/framework.h"
 
 namespace pw::uart {
 namespace {