Add modules for converting java modules between host and device

java_device_for_host and java_host_for_device allow treating a
device module as a host module and vice versa.  They will be useful
for converting layoutlib and robolectric to Soong, as these modules
run device java code on the host.

Bug: 117920228
Test: device_host_converter_test.go
Change-Id: Ia9a371fb41a97bc16338097f3ce8b40099744167

Android.bp

@@ -250,6 +250,7 @@ bootstrap_go_package {
         "java/app_builder.go",
         "java/app.go",
         "java/builder.go",
+        "java/device_host_converter.go",
         "java/dex.go",
         "java/dexpreopt.go",
         "java/dexpreopt_bootjars.go",
@@ -275,6 +276,7 @@ bootstrap_go_package {
     ],
     testSrcs: [
         "java/app_test.go",
+        "java/device_host_converter_test.go",
         "java/dexpreopt_test.go",
         "java/dexpreopt_bootjars_test.go",
         "java/java_test.go",