[K/N] Remove LLVM coverage

The -Xcoverage feature has not worked and has been disabled for a while.
This fix removes it, and all of its uses.


Co-authored-by: Troels Lund <troels@google.com>


Merge-request: KOTLIN-MR-821
Merged-by: Alexander Shabalin <alexander.shabalin@jetbrains.com>

kotlin-native/backend.native/tests/samples/build.gradle.kts

@@ -58,7 +58,6 @@ val buildSamplesWithPlatformLibs by tasks.creating {
         dependsOn(":objc:assemble")
         dependsOn(":opengl:assemble")
         dependsOn(":uikit:assemble")
-        dependsOn(":coverage:assemble")
         dependsOn(":watchos:assemble")
     }