[sanitizer] Add more aarch64 workers

[gkistanova]

LGTM.

buildbot/osuosl/master/config/builders.py

# with large memory usage, so assign them to different workers.
     ],
     'builddir': "sanitizer-x86_64-linux-android",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory()},
 
     {'name' : "sanitizer-aarch64-linux-bootstrap-asan",
     'tags'  : ["sanitizer"],
     'workernames' : [
         "sanitizer-buildbot7",
+        "sanitizer-buildbot9",
+        "sanitizer-buildbot11",
     ],
     'builddir': "sanitizer-aarch64-linux-bootstrap-asan",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory(
         extra_depends_on_projects=["mlir", "clang-tools-extra"]
     )},
 
     {'name' : "sanitizer-aarch64-linux-bootstrap-hwasan",
     'tags'  : ["sanitizer"],
     'workernames' : [
         "sanitizer-buildbot7",
         "sanitizer-buildbot8",
+        "sanitizer-buildbot9",
+        "sanitizer-buildbot11",
     ],
     'builddir': "sanitizer-aarch64-linux-bootstrap-hwasan",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory(
         extra_depends_on_projects=["mlir", "clang-tools-extra"]
     )},
 
     {'name' : "sanitizer-aarch64-linux-bootstrap-msan",
     'tags'  : ["sanitizer"],
     'workernames' : [
         "sanitizer-buildbot8",
+        "sanitizer-buildbot10",
+        "sanitizer-buildbot12",
     ],
     'builddir': "sanitizer-aarch64-linux-bootstrap-msan",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory(
         extra_depends_on_projects=["mlir", "clang-tools-extra"]
     )},
 
     {'name' : "sanitizer-aarch64-linux-bootstrap-ubsan",
     'tags'  : ["sanitizer"],
     'workernames' : [
         "sanitizer-buildbot8",
+        "sanitizer-buildbot10",
+        "sanitizer-buildbot12",
     ],
     'builddir': "sanitizer-aarch64-linux-bootstrap-ubsan",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory(
         extra_depends_on_projects=["mlir", "clang-tools-extra"]
     )},
 
     {'name' : "sanitizer-aarch64-linux-fuzzer",
     'tags'  : ["sanitizer"],
     'workernames' : [
         "sanitizer-buildbot7",
+        "sanitizer-buildbot9",
+        "sanitizer-buildbot11",
     ],
     'builddir': "sanitizer-aarch64-linux-fuzzer",
     'factory' : SanitizerBuilder.getSanitizerBuildFactory()},
 
     {'name' : "sanitizer-ppc64be-linux",
     'tags'  : ["sanitizer", "ppc"],
     'workernames' : ["ppc64be-sanitizer"],
     'builddir': "sanitizer-ppc64be",

buildbot/osuosl/master/config/workers.py

return [
         create_worker("sanitizer-buildbot2", properties={'jobs': 64}, max_builds=3),
         create_worker("sanitizer-buildbot3", properties={'jobs': 64}, max_builds=3),
         create_worker("sanitizer-buildbot4", properties={'jobs': 64}, max_builds=3),
         create_worker("sanitizer-buildbot5", properties={'jobs': 64}, max_builds=3),
         create_worker("sanitizer-buildbot6", properties={'jobs': 64}, max_builds=3),
         # aarch64 GCE instances
         create_worker("sanitizer-buildbot7", properties={'jobs': 48}, max_builds=3),
         create_worker("sanitizer-buildbot8", properties={'jobs': 48}, max_builds=3),
+        create_worker("sanitizer-buildbot9", properties={'jobs': 48}, max_builds=3),
+        create_worker("sanitizer-buildbot10", properties={'jobs': 48}, max_builds=3),
+        create_worker("sanitizer-buildbot11", properties={'jobs': 48}, max_builds=3),
+        create_worker("sanitizer-buildbot12", properties={'jobs': 48}, max_builds=3),
 
         # POWER 8 PowerPC AIX 7.2
         create_worker("aix-ppc64", properties={'jobs': 10}, max_builds=1),
 
         # IBM z13 (s390x), Ubuntu 16.04.2
         create_worker("systemz-1", properties={'jobs': 4, 'vcs_protocol': 'https'}, max_builds=4),
 
         # Windows Server 2012 x86_64 16-core GCE instance