Move JUnit4 usage to separate module

Fixes: 138451391
Test: ./gradlew bench:b-c:cC bench:b-j:cC bench:b-b:cC
Test: ./gradlew compose:compose-runtime-benchmark:assembleDebug

This enables us to implement alternate APIs on top of BenchmarkState
in the future.

Change-Id: I91b8260c06baf58411286391345a0603d94781d9

diff --git a/settings.gradle b/settings.gradle
index 901e499..e953056 100644
--- a/settings.gradle
+++ b/settings.gradle

@@ -60,6 +60,7 @@
 includeProject(":asynclayoutinflater", "asynclayoutinflater")
 includeProject(":autofill", "autofill")
 includeProject(":benchmark:benchmark-common", "benchmark/common")
+includeProject(":benchmark:benchmark-junit4", "benchmark/junit4")
 includeProject(":benchmark:benchmark-benchmark", "benchmark/benchmark")
 includeProject(":benchmark:benchmark-gradle-plugin", "benchmark/gradle-plugin")
 includeProject(":benchmark:integration-tests:startup-benchmark", "benchmark/integration-tests/startup-benchmark")