Kotlin: Add test showing missing java modifier

Author: tamasvajk

java/ql/integration-tests/posix-only/kotlin/java_modifiers/libsrc/extlib/A.java

@@ -0,0 +1,6 @@
+package extlib;
+
+public class A {
+  protected void m() {}
+}
+

java/ql/integration-tests/posix-only/kotlin/java_modifiers/test.expected

@@ -0,0 +1,2 @@
+| extlib.jar/extlib/A.class:0:0:0:0 | m |  |
+| test.kt:4:12:4:22 | m | override, protected |

java/ql/integration-tests/posix-only/kotlin/java_modifiers/test.kt

@@ -0,0 +1,6 @@
+import extlib.A;
+
+class B : A() {
+  override fun m() { }
+}
+

java/ql/integration-tests/posix-only/kotlin/java_modifiers/test.py

@@ -0,0 +1,10 @@
+from create_database_utils import *
+import glob
+
+# Compile Java untraced. Note the Java source is hidden under `javasrc` so the Kotlin compiler 
+# will certainly reference the jar, not the source or class file for extlib.Lib
+
+os.mkdir('build')
+runSuccessfully(["javac"] + glob.glob("libsrc/extlib/*.java") + ["-d", "build"])
+runSuccessfully(["jar", "cf", "extlib.jar", "-C", "build", "extlib"])
+run_codeql_database_create(["kotlinc test.kt -cp extlib.jar"], lang="java")

java/ql/integration-tests/posix-only/kotlin/java_modifiers/test.ql

@@ -0,0 +1,6 @@
+import java
+
+query predicate mods(Method m, string modifiers) {
+  m.getName() = "m" and
+  modifiers = concat(string s | m.hasModifier(s) | s, ", ")
+}