build: move system and samples test from Node 10 to Node 12 (#919)

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Source-Link: googleapis/synthtool@05de3e1

Author: yoshi-automation

.kokoro/continuous/node10/lint.cfg renamed to .kokoro/continuous/node12/lint.cfg

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/cloud-debug-nodejs.git",
-        "sha": "e27cde42676f35e20b43575bed0e116a9491bb05"
+        "sha": "4de5ab77e80a88c2632beafd269597b135fb0687"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5747555f7620113d9a2078a48f4c047a99d31b3e"
+        "sha": "05de3e1e14a0b07eab8b474e669164dbd31f81fb"
       }
     }
   ],
@@ -29,19 +29,19 @@
     ".kokoro/common.cfg",
     ".kokoro/continuous/node10/common.cfg",
     ".kokoro/continuous/node10/docs.cfg",
-    ".kokoro/continuous/node10/lint.cfg",
-    ".kokoro/continuous/node10/samples-test.cfg",
-    ".kokoro/continuous/node10/system-test.cfg",
     ".kokoro/continuous/node10/test.cfg",
     ".kokoro/continuous/node12/common.cfg",
+    ".kokoro/continuous/node12/lint.cfg",
+    ".kokoro/continuous/node12/samples-test.cfg",
+    ".kokoro/continuous/node12/system-test.cfg",
     ".kokoro/continuous/node12/test.cfg",
     ".kokoro/docs.sh",
     ".kokoro/lint.sh",
     ".kokoro/populate-secrets.sh",
     ".kokoro/presubmit/node10/common.cfg",
-    ".kokoro/presubmit/node10/samples-test.cfg",
-    ".kokoro/presubmit/node10/system-test.cfg",
     ".kokoro/presubmit/node12/common.cfg",
+    ".kokoro/presubmit/node12/samples-test.cfg",
+    ".kokoro/presubmit/node12/system-test.cfg",
     ".kokoro/presubmit/node12/test.cfg",
     ".kokoro/publish.sh",
     ".kokoro/release/docs-devsite.cfg",