Rename native code coverage paths product variables in Soong.

Rename `CoveragePath` and `CoverageExcludePaths` as
`NativeCoveragePath` and `NativeCoverageExcludePaths` (resp.).
Also rename function `android.CoverageEnabledForPath` as
`android.NativeCoverageEnabledForPath`.

Test: m nothing
Bug: 158212027
Change-Id: Id2c11a638e88088096420b537effa866d7667304
diff --git a/cc/coverage.go b/cc/coverage.go
index f885fcb..1a559a9 100644
--- a/cc/coverage.go
+++ b/cc/coverage.go
@@ -180,7 +180,7 @@
 
 		if needCoverageVariant {
 			// Coverage variant is actually built with coverage if enabled for its module path
-			needCoverageBuild = ctx.DeviceConfig().CoverageEnabledForPath(ctx.ModuleDir())
+			needCoverageBuild = ctx.DeviceConfig().NativeCoverageEnabledForPath(ctx.ModuleDir())
 		}
 	}