Mark test that passes when name hashing is enabled.

There's one test that starts to pass when we enable name hashing. It's
`import-class` which tests whether tracking of dependencies that arise
from imports is properly tracked. The name hashing algorithm uses different
dependency tracking compared to the old algorithm and the new dependency
extraction logic does handle import tree nodes properly so the test passes.

We "mark" the test passing by copying it and enabling the name hashing
flag in it. This is done similarly as in 940f7ff46d.

sbt/src/sbt-test/source-dependencies/import-class-name-hashing/A.scala

@@ -0,0 +1,3 @@
+package a
+
+class A

sbt/src/sbt-test/source-dependencies/import-class-name-hashing/B.scala

@@ -0,0 +1 @@
+import a.A

sbt/src/sbt-test/source-dependencies/import-class-name-hashing/build.sbt

@@ -0,0 +1 @@
+incOptions := incOptions.value.withNameHashing(true)

sbt/src/sbt-test/source-dependencies/import-class-name-hashing/changes/A.scala

@@ -0,0 +1 @@
+package a

sbt/src/sbt-test/source-dependencies/import-class-name-hashing/test

@@ -0,0 +1,8 @@
+> compile
+
+# remove class a.A
+$ copy-file changes/A.scala A.scala
+
+# 'import a.A' should now fail in B.scala
+# succeeds because scalac doesn't track this dependency
+-> compile