liblog: benchmarks use google-benchmark library

Remove our circa 2014 snapshot of the google benchmarking library, and
use the now very stable google-benchmark suite. Some porting effort,
and deal with some benchmarking saddle points that take too long to
sort out. Focus on minimal API changes, _odd_ new behaviors, and style.

Test: liblog_benchmarks, ensure results in about the same range
Bug: 69423514
Change-Id: I2add1df9cb664333bcf983b57121ae151b26935b
diff --git a/liblog/tests/Android.mk b/liblog/tests/Android.mk
index 39b52ac..cfa849b 100644
--- a/liblog/tests/Android.mk
+++ b/liblog/tests/Android.mk
@@ -24,13 +24,12 @@
 test_tags := tests
 
 benchmark_c_flags := \
-    -Ibionic/tests \
-    -Wall -Wextra \
+    -Wall \
+    -Wextra \
     -Werror \
     -fno-builtin \
 
 benchmark_src_files := \
-    benchmark_main.cpp \
     liblog_benchmark.cpp
 
 # Build benchmarks for the device. Run with:
@@ -41,7 +40,7 @@
 LOCAL_CFLAGS += $(benchmark_c_flags)
 LOCAL_SHARED_LIBRARIES += liblog libm libbase
 LOCAL_SRC_FILES := $(benchmark_src_files)
-include $(BUILD_NATIVE_TEST)
+include $(BUILD_NATIVE_BENCHMARK)
 
 # -----------------------------------------------------------------------------
 # Unit tests.