Migrate Rust to LLVM coverage.

Bug: 177675913
Test: Manually compile, run, and see output with llvm-cov.
Change-Id: I66729cff87a848782e9fa1b95cbbc06318c5761a
diff --git a/rust/library.go b/rust/library.go
index 4ac52b4..6433285 100644
--- a/rust/library.go
+++ b/rust/library.go
@@ -452,26 +452,22 @@
 		fileName = library.getStem(ctx) + ctx.toolchain().RlibSuffix()
 		outputFile = android.PathForModuleOut(ctx, fileName)
 
-		outputs := TransformSrctoRlib(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
-		library.coverageFile = outputs.coverageFile
+		TransformSrctoRlib(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
 	} else if library.dylib() {
 		fileName = library.getStem(ctx) + ctx.toolchain().DylibSuffix()
 		outputFile = android.PathForModuleOut(ctx, fileName)
 
-		outputs := TransformSrctoDylib(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
-		library.coverageFile = outputs.coverageFile
+		TransformSrctoDylib(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
 	} else if library.static() {
 		fileName = library.getStem(ctx) + ctx.toolchain().StaticLibSuffix()
 		outputFile = android.PathForModuleOut(ctx, fileName)
 
-		outputs := TransformSrctoStatic(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
-		library.coverageFile = outputs.coverageFile
+		TransformSrctoStatic(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
 	} else if library.shared() {
 		fileName = library.sharedLibFilename(ctx)
 		outputFile = android.PathForModuleOut(ctx, fileName)
 
-		outputs := TransformSrctoShared(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
-		library.coverageFile = outputs.coverageFile
+		TransformSrctoShared(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
 	}
 
 	if !library.rlib() && library.stripper.NeedsStrip(ctx) {
@@ -480,15 +476,6 @@
 		library.strippedOutputFile = android.OptionalPathForPath(strippedOutputFile)
 	}
 
-	var coverageFiles android.Paths
-	if library.coverageFile != nil {
-		coverageFiles = append(coverageFiles, library.coverageFile)
-	}
-	if len(deps.coverageFiles) > 0 {
-		coverageFiles = append(coverageFiles, deps.coverageFiles...)
-	}
-	library.coverageOutputZipFile = TransformCoverageFilesToZip(ctx, coverageFiles, library.getStem(ctx))
-
 	if library.rlib() || library.dylib() {
 		library.flagExporter.exportLinkDirs(deps.linkDirs...)
 		library.flagExporter.exportDepFlags(deps.depFlags...)