Do not set different score to non-string values

Non-string values in a cache is supposed to choose one from them.
Due to the change of da1c9f7a, there was a regression on scoring for
matching functions.  So reverting the behavior for evaluating non-string
values to the previous one.

Fixes fontconfig/fontconfig#286
11 jobs for issue/286 in 9 minutes and 34 seconds (queued for 10 seconds)
Status Name Job ID Coverage
  Build
passed meson android arm64 fedora #11610447

00:01:28

passed meson macos #11610445
gst-macos-10.15

00:04:27

passed meson-mingw-w64-build #11610442

00:06:49

manual meson msys2 #11610446
docker windows 1809 allowed to fail manual
passed meson-shared-build #11610440

00:07:27

passed meson-static-build #11610441

00:07:11

passed meson vs2017 amd64 #11610443
docker windows 1809

00:01:36

passed meson vs2017 x86 #11610444
docker windows 1809

00:01:32

passed mingw-build #11610439

00:08:05

passed shared-build #11610437

00:09:34

passed static-build #11610438

00:08:02