meson: use gtest protocol for gtest based tests when possible

With the `gtest` protocol meson will add some extra arguments to the
test to generate better junit results, which may be useful. This
protocol is only available in meson 0.55.0+, so keep using the default
`exitcode` protocol for meson older than that.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8484>

meson.build

@@ -30,6 +30,13 @@ project(
   default_options : ['buildtype=debugoptimized', 'b_ndebug=if-release', 'c_std=c11', 'cpp_std=c++14']
 )
 
+# For meson >= 0.55.0, meson can inject some extra arguments to get richer
+# results from gtest based tests.
+gtest_test_protocol = 'exitcode'
+if meson.version().version_compare('>= 0.55.0')
+  gtest_test_protocol = 'gtest'
+endif
+
 cc = meson.get_compiler('c')
 cpp = meson.get_compiler('cpp')