Clean resources from previous build's volatiles (#2946)

Fixes #2946

When test projects are built, their directories are polluted with build
results. This makes tests using those project unreliable.

This change removes some of the pollution to stabilize subsequent tests.

tycho-compiler-plugin/pom.xml

@@ -10,7 +10,8 @@
  -    Sonatype Inc. - initial API and implementation
  -->
 
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
@@ -87,5 +88,24 @@
 			<scope>test</scope>
 		</dependency>
 	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-clean-plugin</artifactId>
+				<configuration>
+					<failOnError>false</failOnError>
+					<filesets>
+						<fileset>
+							<directory>${project.basedir}/src/test/resources/projects</directory>
+							<includes>
+								<include>**/bin/**</include>
+							</includes>
+						</fileset>
+					</filesets>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
 
 </project>