Add support for Rust C libraries.

Adds the ability for rust modules to be compiled as C libraries, and
allows cc modules to depend on these rust-generated modules. This also
means that soong-rust should not have any dependencies on soong-cc aside
from what's required for testing.

There's a couple small fixes included as well:

 - A bug in libNameFromFilePath that caused issues when library's had
 "lib" in their name.
 - VariantName is removed from rust library MutatedProperties since this
 was unused.

Bug: 140726209
Test: Soong tests pass.
Test: Example cc_binary can include a rust shared library as a dep.
Test: m crosvm.experimental
Change-Id: Ia7deed1345d2423001089014cc65ce7934123da4

cc/sanitize.go

@@ -873,7 +873,7 @@ func sanitizerRuntimeMutator(mctx android.BottomUpMutatorContext) {
 		}
 
 		if mctx.Device() && runtimeLibrary != "" {
-			if inList(runtimeLibrary, *llndkLibraries(mctx.Config())) && !c.static() && c.useVndk() {
+			if inList(runtimeLibrary, *llndkLibraries(mctx.Config())) && !c.static() && c.UseVndk() {
 				runtimeLibrary = runtimeLibrary + llndkLibrarySuffix
 			}
 
@@ -963,7 +963,7 @@ func sanitizerMutator(t sanitizerType) func(android.BottomUpMutatorContext) {
 						if t == cfi {
 							appendStringSync(c.Name(), cfiStaticLibs(mctx.Config()), &cfiStaticLibsMutex)
 						} else if t == hwasan {
-							if c.useVndk() {
+							if c.UseVndk() {
 								appendStringSync(c.Name(), hwasanVendorStaticLibs(mctx.Config()),
 									&hwasanStaticLibsMutex)
 							} else {