Make OutputFileForModule work for AllowMissingDependencies

Report missing output files as missing dependencies when
AllowMissingDependencies is enabled.  This will fix
AllowMissingDependencies builds where a dependency module is
present but missing support for a specific architecture.

Bug: 250918230
Test: lunch aosp_riscv64-userdebug && m ALLOW_MISSING_DEPENDENCIES=true nothing
Test: TestOutputFileForModule
Change-Id: I95e96e3e7cb3df7bf678ed628b45baf659addbad