Inherit parent's extra Clang arguments when creating an interface build sub-invocation.

We would like to make sure they get propagated to downstream transitive Clang module dependencies also.

Resolves rdar://101923680

test/ModuleInterface/Inputs/macro-only-module/module.modulemap

@@ -0,0 +1 @@
+module OnlyWithMacro { header "OnlyWithMacro.h" }