Bp2build support for sdk_version and java_version.

This CL adds java_version and sdk_version support to bp2build
converters for
   - java library
   - java binary
   - android library
   - android binary
   - android library import

Although java import doesn't support java_version and sdk_version, the
neverlink java_library wrapper around a java_import must specify a
sdk_version when targetting a device. "none" is used by convention.

Change-Id: I22a69dea2e351858368df69ed6a703b568d613ea
Bug: 215230098
Test: Presubmits
diff --git a/bp2build/java_proto_conversion_test.go b/bp2build/java_proto_conversion_test.go
index d25b7c4..f546cf4 100644
--- a/bp2build/java_proto_conversion_test.go
+++ b/bp2build/java_proto_conversion_test.go
@@ -114,13 +114,17 @@
 				"java_lite_proto_library",
 				"java-protos_java_proto_lite",
 				AttrNameToString{
-					"deps": `[":java-protos_proto"]`,
+					"deps":         `[":java-protos_proto"]`,
+					"java_version": `"7"`,
 				}),
 			MakeBazelTarget("java_library", "java-protos", AttrNameToString{
-				"exports":   `[":java-protos_java_proto_lite"]`,
-				"javacopts": `["-source 1.7 -target 1.7"]`,
+				"exports":      `[":java-protos_java_proto_lite"]`,
+				"java_version": `"7"`,
 			}),
-			MakeNeverlinkDuplicateTarget("java_library", "java-protos"),
+			MakeNeverlinkDuplicateTargetWithAttrs(
+				"java_library",
+				"java-protos",
+				AttrNameToString{"java_version": `"7"`}),
 		},
 	})
 }