kallsyms: make SpKallsyms more testable

This allows us to pass in the file to read from, and adds a quick test
case to view the parsed output. It also fixes a base-10 vs base-16
mistake in parsing addresses.

tests/meson.build

@@ -18,6 +18,11 @@ test_capture_cursor = executable('test-capture-cursor',
 )
 test('test-capture-cursor', test_capture_cursor, env: test_env)
 
+test_kallsyms = executable('test-kallsyms',
+  ['test-kallsyms.c', '../lib/sp-kallsyms.c'],
+  dependencies: libsysprof_dep,
+)
+
 if get_option('enable_gtk')
 
   test_model_filter = executable('test-model-filter',