plugins: only include tested languages

The plugin tests were always enabled because they were always searched
for. Instead, search for the testing languages.

Change-Id: I974e63270bfc9b589706fd8a9b6e8bb59ab82b25
Merge topic 'data-download-without-testing' into next

7f2ee05e plugins: only include tested languages
plugins: allow static plugins to be loaded dynamically

Change-Id: I9fc37d4ef87534cbc159d72e734ea6bda35985ca
plugins: enable the plugin dialog in static builds

Change-Id: I4164bcae4334c91114f512fc658c3588088c06f2
Merge topic 'static-plugins' into next

a6069df3 plugins: enable the plugin dialog in static builds
43f9ae27 plugins: allow static plugins to be loaded dynamically