base: extract {ASSERT,EXPECT}_MATCH helpers from debuggerd_test.

Add some helper macros that perform regex string matching to
<android-base/test_utils.h>.

Test: libbase_test32/64 on host
Change-Id: I1b0f03dc73f8b4fdfb8ac6c75d59ef421e0e9640
diff --git a/base/Android.bp b/base/Android.bp
index ad0edf4..01800af 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -116,6 +116,7 @@
         "stringprintf_test.cpp",
         "strings_test.cpp",
         "test_main.cpp",
+        "test_utils_test.cpp",
     ],
     target: {
         android: {