Save screenshot to build output directory

eclipse-platform/eclipse.platform.swt#3303

As screenshots are effectively a build artifact, save them in build
output directory (target/ by default).

SWT does not use Platform, so existing heuristics have not worked in
GitHub Actions, abandoning screenshots in /tmp without archiving into
artifacts.

The change breaks existing Gerrit jobs, but as Gerrit is no longer used,
this should be fine.

Author: basilevs

.github/workflows/mavenBuild.yml

@@ -95,3 +95,4 @@ jobs:
         path: |
           ${{ github.workspace }}/**/target/surefire-reports/*.xml
           ${{ github.workspace }}/**/results/**/*.png
+          ${{ github.workspace }}/**/target/screenshots/*.png

eclipse-platform-parent/pom.xml

@@ -131,6 +131,7 @@
     <!-- system specific JVM args; if needed provided by system properties to the build command -->
     <surefire.systemProperties></surefire.systemProperties>
     <surefire.timeout>1200</surefire.timeout>
+    <surefire.screenshot_directory>${project.build.directory}/screenshots</surefire.screenshot_directory>
     <java.version>17</java.version>
     <printApiMessages>false</printApiMessages>
     <failOnJavadocErrors>false</failOnJavadocErrors>
@@ -343,6 +344,11 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-surefire-plugin</artifactId>
           <version>${surefire.version}</version>
+          <configuration>
+            <systemPropertyVariables>
+                <eclipse.screenshot_directory>${surefire.screenshot_directory}</eclipse.screenshot_directory>
+            </systemPropertyVariables>
+          </configuration>
         </plugin>
          <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -434,6 +440,9 @@
             <enableAssertions>true</enableAssertions>
             <argLine>${surefire.testArgLine} ${surefire.platformSystemProperties} ${surefire.systemProperties} ${surefire.moduleProperties}</argLine>
             <quiet>true</quiet>
+            <systemProperties>
+                <eclipse.screenshot_directory>${surefire.screenshot_directory}</eclipse.screenshot_directory>
+            </systemProperties>
           </configuration>
         </plugin>
         <plugin>

eclipse.platform.releng/bundles/org.eclipse.test/src/org/eclipse/test/Screenshots.java

@@ -139,6 +139,10 @@ private static File getJunitReportOutput() {
 				}
 			}
 		}
+		String path = System.getProperty("eclipse.screenshot_directory");
+		if (path != null) {
+			return new File(path);
+		}
 		return null;
     }