Select best matching target environment for p2install

Currently a p2 provisioned install always use the running target to
provision what is also the best option most of the time. In case where
there is no matching one this can lead to failing installs.

This now allows to specify the environments and shows a warning if the
running one does not has any match.

tycho-surefire/tycho-surefire-plugin/src/main/java/org/eclipse/tycho/surefire/AbstractEclipseTestMojo.java

@@ -649,7 +649,10 @@ private EquinoxInstallation createProvisionedInstallation() throws MojoExecution
             } else {
                 installationBuilder.setDestination(work);
             }
-            return installationBuilder.install();
+            List<TargetEnvironment> list = getTestTargetEnvironments();
+            TargetEnvironment env = list.isEmpty() ? runningEnvironment : list.get(0);
+            getLog().info("Provisioning with environment " + env + "...");
+            return installationBuilder.install(env);
         } catch (Exception ex) {
             throw new MojoExecutionException(ex.getMessage(), ex);
         }

tycho-surefire/tycho-surefire-plugin/src/main/java/org/eclipse/tycho/surefire/provisioning/ProvisionedInstallationBuilder.java

@@ -97,10 +97,10 @@ public void setInstallFeatures(boolean installFeatures) {
         this.installFeatures = installFeatures;
     }
 
-    public EquinoxInstallation install() throws Exception {
+    public EquinoxInstallation install(TargetEnvironment main) throws Exception {
         validate();
         publishPlainBundleJars();
-        executeDirector();
+        executeDirector(main);
         return new ProvisionedEquinoxInstallation(effectiveDestination, bundleReader);
     }
 
@@ -121,7 +121,7 @@ private void publishPlainBundleJars() throws Exception {
         artifactRepos.add(bundlesRepoURI);
     }
 
-    private void executeDirector() throws MojoFailureException {
+    private void executeDirector(TargetEnvironment env) throws MojoFailureException {
         DirectorRuntime.Command command = directorRuntime.newInstallCommand();
         command.addMetadataSources(metadataRepos);
         command.addArtifactSources(artifactRepos);
@@ -131,7 +131,7 @@ private void executeDirector() throws MojoFailureException {
         command.setDestination(effectiveDestination);
         command.setProfileName(profileName);
         command.setInstallFeatures(installFeatures);
-        command.setEnvironment(TargetEnvironment.getRunningEnvironment());
+        command.setEnvironment(env);
         log.info("Installing IUs " + ius + " to " + effectiveDestination);
         try {
             command.execute();