[libc] Add a riscv64 worker and two builders on it.

[gkistanova]

Thanks, Siva!
LGTM.

Please ping me with the password for this worker before committing the patch.

buildbot/osuosl/master/config/builders.py

# libc Builders.
     'tags'  : ["libc"],
     'workernames' : ["libc-lint-worker"],
     'builddir': "libc-x86_64-debian-dbg-lint",
     'factory' : AnnotatedBuilder.getAnnotatedBuildFactory(
                     script="libc-linux.py",
                     depends_on_projects=['llvm', 'libc'],
                     extra_args=['--debug'])},
 
+    {'name' : 'libc-riscv64-debian-dbg',
+    'tags'  : ["libc"],
+    'workernames' : ['libc-riscv64-debian'],
+    'builddir': 'libc-riscv64-debian-dbg',
+    'factory' : AnnotatedBuilder.getAnnotatedBuildFactory(
+                    script="libc-linux.py",
+                    depends_on_projects=['llvm', 'libc'],
+                    extra_args=['--debug'])},
+
+    {'name' : "libc-riscv64-debian-fullbuild-dbg",
+    'tags'  : ["libc"],
+    'workernames' : ["libc-riscv64-debian"],
+    'builddir': "libc-riscv64-debian-fullbuild-dbg",
+    'factory' : AnnotatedBuilder.getAnnotatedBuildFactory(
+                    script="libc-linux.py",
+                    depends_on_projects=['llvm', 'libc'],
+                    extra_args=['--debug'])},
+
 # Flang builders.
 
     {'name' : "flang-aarch64-dylib",
     'tags'  : ["flang"],
     'workernames' : ["linaro-flang-aarch64-dylib"],
     'builddir': "flang-aarch64-dylib",
     'factory' : UnifiedTreeBuilder.getCmakeWithNinjaBuildFactory(
                     clean=True,

buildbot/osuosl/master/config/status.py

reporters.MailNotifier(
         builders = ["libc-x86_64-debian", "libc-x86_64_debian-dbg",
                     "libc-x86_64-debian-dbg-runtimes-build",
                     "libc-x86_64-debian-dbg-asan", "libc-aarch64-ubuntu-dbg",
                     "libc-x86_64-windows-dbg", "libc-arm32-debian-dbg",
                     "libc-aarch64-ubuntu-fullbuild-dbg",
                     "libc-x86_64-debian-fullbuild-dbg",
                     "libc-x86_64-debian-gcc-fullbuild-dbg",
                     "libc-x86_64-debian-fullbuild-dbg-asan",
+                    "libc-riscv64-debian-dbg",
+                    "libc-riscv64-debian-fullbuild-dbg",
                     "libc-x86_64-debian-dbg-lint"]),
     reporters.MailNotifier(
         fromaddr = "[e-mail]",
         sendToInterestedUsers = False,
         extraRecipients = ["[e-mail]"],
         subject = "Sphinx build %(builder)s Failure",
         mode = "failing",
         builders = ["publish-sphinx-docs"]),

buildbot/osuosl/master/config/workers.py

return [
         create_worker("libc-x86_64-debian", properties={'jobs': 32}, max_builds=2),
 
         # Debian x86_64 Intel Skylake 32 CPUs, 128 GB RAM
         create_worker("libc-x86_64-debian-fullbuild", properties={'jobs': 32}, max_builds=2),
 
         # Debian x86_64 Intel Cascade Lake 8 CPU, 32 GB RAM
         create_worker("libc-lint-worker", properties={'jobs': 16}, max_builds=2),
 
+        # Debian riscv64 4 CPU, 4 GB RAM
+        create_worker("libc-riscv64-debian", properties={'jobs': 4}, max_builds=1),
+
         # Windows Server on Xeon Gold 6130 (2x2.1GHz), 128Gb of RAM
         create_worker("as-builder-1", properties={
                         'remote_test_host': 'jetson6.lab.llvm.org',
                         'remote_test_user': 'ubuntu'
                      },
                      max_builds=1),
 
         # Windows Server on Xeon Gold 6130 (2x2.1GHz), 128Gb of RAM