Switch Mac Intel GPU jobs to target 10.12 bots instead of 10.10.

content/test/gpu/generate_buildbot_json.py

Index: content/test/gpu/generate_buildbot_json.py
diff --git a/content/test/gpu/generate_buildbot_json.py b/content/test/gpu/generate_buildbot_json.py
index 9399235c9d95e2cac96b035047d968f58b408fb1..fca37658adadc8e750ec402cf0c7d993ec184de6 100755
--- a/content/test/gpu/generate_buildbot_json.py
+++ b/content/test/gpu/generate_buildbot_json.py
@@ -54,7 +54,7 @@ WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
       ],
       'build_config': 'Release',
@@ -65,7 +65,7 @@ WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
       ],
       'build_config': 'Debug',
@@ -323,7 +323,7 @@ FYI_WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
       ],
       'build_config': 'Release',
@@ -334,7 +334,7 @@ FYI_WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
       ],
       'build_config': 'Debug',
@@ -433,7 +433,7 @@ FYI_WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
         {
           'gpu': '1002:6821',
@@ -690,7 +690,7 @@ FYI_WATERFALL = {
       'swarming_dimensions': [
         {
           'gpu': '8086:0a2e',
-          'os': 'Mac-10.10'
+          'os': 'Mac-10.12'
         },
       ],
       'build_config': 'Release',