rust: Rename flag providers for clarity

Rename the Rust flag and export info providers to make it more clear
when workign with the Rust exporter vs the cc exporter.

Also renames a test for additional clarity.

Test: m blueprint_tests
Change-Id: I652b55ef000a2cd00f47b1dbfe86713c33ae9d63
diff --git a/rust/prebuilt.go b/rust/prebuilt.go
index e35e510..9bd5111 100644
--- a/rust/prebuilt.go
+++ b/rust/prebuilt.go
@@ -158,7 +158,7 @@
 
 func (prebuilt *prebuiltLibraryDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) buildOutput {
 	prebuilt.flagExporter.exportLinkDirs(android.PathsForModuleSrc(ctx, prebuilt.Properties.Link_dirs).Strings()...)
-	prebuilt.flagExporter.setProvider(ctx)
+	prebuilt.flagExporter.setRustProvider(ctx)
 	srcPath := prebuiltPath(ctx, prebuilt)
 	prebuilt.baseCompiler.unstrippedOutputFile = srcPath
 	return buildOutput{outputFile: srcPath}
@@ -211,7 +211,7 @@
 
 func (prebuilt *prebuiltProcMacroDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) buildOutput {
 	prebuilt.flagExporter.exportLinkDirs(android.PathsForModuleSrc(ctx, prebuilt.Properties.Link_dirs).Strings()...)
-	prebuilt.flagExporter.setProvider(ctx)
+	prebuilt.flagExporter.setRustProvider(ctx)
 	srcPath := prebuiltPath(ctx, prebuilt)
 	prebuilt.baseCompiler.unstrippedOutputFile = srcPath
 	return buildOutput{outputFile: srcPath}