ToolChain: Make sure all ToolChains have a language set

* Add code to toolchains
* Assert that this is the case in the toolchainmanager

Change-Id: I82452689e83279fd9d1afb3140b0070bef9b6cd8
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>

src/plugins/android/androidtoolchain.h

@@ -62,7 +62,8 @@ protected:
     DetectedAbisResult detectSupportedAbis() const override;
 
 private:
-    explicit AndroidToolChain(const ProjectExplorer::Abi &abi, const QString &ndkToolChainVersion, Detection d);
+    explicit AndroidToolChain(const ProjectExplorer::Abi &abi, const QString &ndkToolChainVersion,
+                              Language l, Detection d);
     AndroidToolChain();
     AndroidToolChain(const AndroidToolChain &);