[TSan] Remove ignore_interceptors_accesses flag

Summary:
It has been superseded by the `ignore_noninstrumented_modules` flag and is no longer needed.

Also simplify a test that checks that `mmap_interceptor` respects ignore annotations (`thr->ignore_reads_and_writes `).
Relevant: https://reviews.llvm.org/rL269855

<rdar://problem/46263073> Remove obsolete Apple-specific suppression option

Reviewers: dcoughlin, kubamracek, dvyukov, delcypher

Reviewed By: dvyukov

Subscribers: jfb, llvm-commits, #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D55075

llvm-svn: 350883