Update relevancy for compat packages

rust-sanity disabled, rust always uses latest llvm
binutils-plugin-ar not relevant, llvm-libs compat does not install the
symlink to LLVMgold.so

tests/binutils-plugin-ar/main.fmf

@@ -14,4 +14,8 @@ adjust+:
     enabled: false
     when: distro == rhel-7
 
+  - because: compat llvm-libs does not install LLVMgold.so in bfd-plugins dir
+    enabled: false
+    when: compat is defined
+
 extra-nitrate: TC#0614092

tests/rust-sanity/main.fmf

@@ -21,6 +21,10 @@ adjust+:
       - rust
     when: "collection is not defined"
 
+  - because: "Rust uses latest llvm version, compat packages irrelevant here"
+    enabled: false
+    when: compat is defined
+
   # Requirements for SCL-ized LLVM
   - require+:
       - rust-toolset-1.58-cargo