Handle Scala 2.12.3

Author: olafurpg

lsif-java/src/main/scala/com/sourcegraph/lsif_java/buildtools/GradleBuildTool.scala

@@ -246,9 +246,11 @@ class GradleBuildTool(index: IndexCommand) extends BuildTool("Gradle", index) {
   def semanticdbScalacGroovySyntax(): String =
     BuildInfo
       .semanticdbScalacVersions
+      .removed(
+        "2.12.3"
+      ) // Not supported because the last semanticdb-scalac_2.12.3 release doesn't support the option -P:semanticdb:targetroot:PATH.
       .map { case (key, value) =>
         s"'$key':'$value'"
-      }
-      .mkString("[", ", ", "]")
+      }.mkString("[", ", ", "]")
 
 }

semanticdb-agent/src/main/java/com/sourcegraph/semanticdb_javac/SemanticdbAgent.java

@@ -7,14 +7,12 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.PrintStream;
-import java.lang.instrument.ClassFileTransformer;
 import java.lang.instrument.Instrumentation;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
-import java.security.ProtectionDomain;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.NoSuchElementException;