Refactor CC to prep for Rust sanitizable modules.

Adds a PlatformSanitizable interface which both CC and Rust can
implement so that the sanitizer mutators in CC can sanitize Rust
shared/static libraries appropriately.

Bug: 147140513
Test: m nothing
Change-Id: Ib31103b6c4902a4d5df2565c0d7c981298d100a3
diff --git a/cc/vendor_snapshot.go b/cc/vendor_snapshot.go
index 622ebec..0a89e47 100644
--- a/cc/vendor_snapshot.go
+++ b/cc/vendor_snapshot.go
@@ -247,7 +247,7 @@
 		if m.sanitize != nil {
 			// scs and hwasan export both sanitized and unsanitized variants for static and header
 			// Always use unsanitized variants of them.
-			for _, t := range []sanitizerType{scs, hwasan} {
+			for _, t := range []SanitizerType{scs, hwasan} {
 				if !l.shared() && m.sanitize.isSanitizerEnabled(t) {
 					return false
 				}