meson: Cleanup tests and make them execute again

The tests were previously building but not executing. Fix the build so
they execute and pass again.

Change-Id: I6e29eadd4f51cf47d05f7172f37c76688955ac61
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meson.build b/meson.build
index 47cee55..77f7761 100644
--- a/meson.build
+++ b/meson.build
@@ -10,11 +10,7 @@
     version: '1.0',
 )
 
-build_tests = get_option('tests')
-
 fmt = dependency('fmt')
-gmock = dependency('gmock')
-gtest = dependency('gtest', main: true)
 
 conf = configuration_data()
 conf.set_quoted('BUSNAME_PREFIX', get_option('busname-prefix'))
@@ -97,5 +93,7 @@
     install: true)
 
 subdir('msl')
-subdir('test')
+if not get_option('tests').disabled()
+  subdir('test')
+endif
 subdir('tools')