Fix that plugins were wrongly indirectly enabled when testing

Since the disabling of all plugins except tested onces was implemented
as an afterthought, it did not update the indirectly enabled plugins.
Instead, update the list of enabled/disabled plugins in the
optionsparser like for the -(no)load options, and trigger the update of
indirectly enabled plugins afterwards. Also take test dependencies into
account when indirectly enabling plugins directly.

Change-Id: I59d6c05de69a3073576155f7bd6201f1cd44697c
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/libs/extensionsystem/pluginspec_p.h

@@ -103,7 +103,7 @@ public:
     static bool isValidVersion(const QString &version);
     static int versionCompare(const QString &version1, const QString &version2);
 
-    void enableDependenciesIndirectly();
+    QList<PluginSpec *> enableDependenciesIndirectly(bool enableTestDependencies = false);
 
     bool readMetaData(const QJsonObject &pluginMetaData);