PHPC-1299: Add Ubuntu 16.04/ARM64.

Author: derickr

.evergreen/config.yml

@@ -657,6 +657,9 @@ axes:
       - id: rhel74-zseries
         display_name: "RHEL 7.4 zSeries"
         run_on: rhel72-zseries-test
+      - id: ubuntu1604-arm64
+        display_name: "Ubuntu 16.04 ARM64"
+        run_on: ubuntu1604-arm64-large
 
 buildvariants:
 
@@ -685,7 +688,7 @@ buildvariants:
 
 - matrix_name: "mongo-30-php7"
   matrix_spec: {"os-php7": "*", "versions": ["3.0", "3.2", "3.4"], "php-versions": "7.2" }
-  exclude_spec: [ {"os-php7": "rhel71-power8", "versions": "3.0", "php-versions": "7.2"}, {"os-php7": "rhel74-zseries", "versions": ["3.0", "3.2"], "php-versions": "7.2"} ]
+  exclude_spec: [ {"os-php7": "rhel71-power8", "versions": "3.0", "php-versions": "7.2"}, {"os-php7": "rhel74-zseries", "versions": ["3.0", "3.2"], "php-versions": "7.2"} , {"os-php7": "ubuntu1604-arm64", "versions": ["3.0", "3.2"], "php-versions": "7.2"} ]
   display_name: "${versions}/${php-versions} — ${os-php7}"
   tasks:
      - name: "test-standalone-old"