Use Config/DeviceConfig functions to access ProductVariables

An upcoming change will stop exporting ProductVariables from Config, so
switch to using existing accessor functions, and add more when they're
missing.

Bug: 76168832
Test: out/soong/build.ninja is identical
Change-Id: Ie0135bdbd2df3258ef3ddb53e5f8fc00aa9b97f7

cc/binary.go

@@ -192,7 +192,7 @@ func (binary *binaryDecorator) linkerInit(ctx BaseModuleContext) {
 
 	if !ctx.toolchain().Bionic() {
 		if ctx.Os() == android.Linux {
-			if binary.Properties.Static_executable == nil && Bool(ctx.Config().ProductVariables.HostStaticBinaries) {
+			if binary.Properties.Static_executable == nil && ctx.Config().HostStaticBinaries() {
 				binary.Properties.Static_executable = BoolPtr(true)
 			}
 		} else {