Copy tools needed by host gtests to testcases directory.

Atest requires that everything is in the testcases directory.
The files are not used yet (this is left to follow-up CLs).

Bug: 147819342
Test: check the generated general-tests.zip ("m general-tests")
Change-Id: Ied22a736e81a7cff03641d18bacd829b86a6ef0b
diff --git a/build/makevars.go b/build/makevars.go
index 1faa0f6..6e66966 100644
--- a/build/makevars.go
+++ b/build/makevars.go
@@ -44,4 +44,12 @@
 	for _, name := range testNames {
 		ctx.Strict("ART_TEST_LIST_"+name, strings.Join(testMap[name], " "))
 	}
+
+	// Create list of copy commands to install the content of the testcases directory.
+	testcasesContent := testcasesContent(ctx.Config())
+	copy_cmds := []string{}
+	for _, key := range android.SortedStringKeys(testcasesContent) {
+		copy_cmds = append(copy_cmds, testcasesContent[key]+":"+key)
+	}
+	ctx.Strict("ART_TESTCASES_CONTENT", strings.Join(copy_cmds, " "))
 }