Added multi-module tests on incremental compilation.

Changing code wasn't required, Java's incremental caches were enough.

jps-plugin/testData/incremental/multiModule/simpleDependencyUnchanged/build.log

@@ -0,0 +1,8 @@
+Cleaning output files:
+out/production/module1/a/A.class
+out/production/module1/a/APackage$module1_a$*.class
+out/production/module1/a/APackage.class
+End of files
+Compiling files:
+module1/src/module1_a.kt
+End of files

jps-plugin/testData/incremental/multiModule/simpleDependencyUnchanged/dependencies.txt

@@ -0,0 +1,2 @@
+module1->
+module2->module1

jps-plugin/testData/incremental/multiModule/simpleDependencyUnchanged/module1_a.kt

@@ -0,0 +1,7 @@
+package a
+
+class A
+
+fun a() {
+    println("I'm an old body")
+}

jps-plugin/testData/incremental/multiModule/simpleDependencyUnchanged/module1_a.kt.new

@@ -0,0 +1,7 @@
+package a
+
+class A
+
+fun a() {
+    println("I'm a new body")
+}

jps-plugin/testData/incremental/multiModule/simpleDependencyUnchanged/module2_b.kt

@@ -0,0 +1,5 @@
+package b
+
+fun b(param: a.A) {
+    a.a()
+}