[libFuzzer] Disable hanging tests on AArch64

[yroux]

Summary

Disable problematic tests which broke AArch64 bots.
Details available in Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=38034

[morehouse]

LGTM

test/fuzzer/counters.test

 XFAIL: ios
+UNSUPPORTED: aarch64
 RUN: %cpp_compiler %S/CounterTest.cpp -o %t-CounterTest
 RUN: not %run %t-CounterTest  -max_len=6 -seed=1 -timeout=15 2>&1 | FileCheck %s --check-prefix=COUNTERS
 
 COUNTERS: INITED {{.*}} {{bits:|ft:}}
 COUNTERS: NEW {{.*}} {{bits:|ft:}} {{[1-9]*}}
 COUNTERS: NEW {{.*}} {{bits:|ft:}} {{[1-9]*}}
 COUNTERS: BINGO

test/fuzzer/disable-leaks.test

 REQUIRES: lsan
+UNSUPPORTED: aarch64
 RUN: %cpp_compiler %S/AccumulateAllocationsTest.cpp -o %t-AccumulateAllocationsTest
 RUN: %run %t-AccumulateAllocationsTest -detect_leaks=1 -runs=100000 2>&1 | FileCheck %s --check-prefix=ACCUMULATE_ALLOCS
 ACCUMULATE_ALLOCS: INFO: libFuzzer disabled leak detection after every mutation
 

test/fuzzer/fuzzer-oom.test

+UNSUPPORTED: aarch64
 RUN: %cpp_compiler %S/OutOfMemoryTest.cpp -o %t-OutOfMemoryTest
 RUN: %cpp_compiler %S/OutOfMemorySingleLargeMallocTest.cpp -o %t-OutOfMemorySingleLargeMallocTest
 RUN: %cpp_compiler %S/AccumulateAllocationsTest.cpp -o %t-AccumulateAllocationsTest
 
 RUN: not %run %t-OutOfMemoryTest -rss_limit_mb=300 2>&1 | FileCheck %s
 
 CHECK: ERROR: libFuzzer: out-of-memory (used: {{.*}}; limit: 300Mb)
 CHECK: Test unit written to ./oom-