build(java): use ENABLE_FLAKYBOT env variable (#719)

* changes without context

        autosynth cannot find the source of changes triggered by earlier changes in this
        repository, or by version upgrades to tools such as linters.

* chore: remove java 7 units check

Source-Author: Neenu Shaji <Neenu1995@users.noreply.github.com>
Source-Date: Wed Jul 28 18:18:26 2021 -0400
Source-Repo: googleapis/synthtool
Source-Sha: 1a2878d6909dd10ca4e3c1b5943d6622e996054e
Source-Link: googleapis/synthtool@1a2878d

* build(java): use ENABLE_FLAKYBOT env variable

Kokoro job config now supports both environment variables during this migration period.

Source-Author: Jeff Ching <chingor@google.com>
Source-Date: Thu Aug 12 10:10:27 2021 -0700
Source-Repo: googleapis/synthtool
Source-Sha: ff01716e16d2c6e87eaf87197b753ac9fcbbed5d
Source-Link: googleapis/synthtool@ff01716

Co-authored-by: Emily Ball <emilyball@google.com>

Author: yoshi-automation

.kokoro/build.sh

@@ -115,7 +115,7 @@ fi
 # fix output location of logs
 bash .kokoro/coerce_logs.sh
 
-if [[ "${ENABLE_BUILD_COP}" == "true" ]]
+if [[ "${ENABLE_FLAKYBOT}" == "true" ]]
 then
     chmod +x ${KOKORO_GFILE_DIR}/linux_amd64/flakybot
     ${KOKORO_GFILE_DIR}/linux_amd64/flakybot -repo=googleapis/google-auth-library-java

.kokoro/nightly/samples.cfg

@@ -33,6 +33,6 @@ env_vars: {
 }
 
 env_vars: {
-  key: "ENABLE_BUILD_COP"
+  key: "ENABLE_FLAKYBOT"
   value: "true"
 }

synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/google-auth-library-java.git",
-        "sha": "dfe118c261aadf137a3cf47a7acb9892c7a6db4d"
+        "sha": "aa7ede1d1c688ba437798f4204820c0506d5d969"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "87254ac89a9559864c0a245d6b150406439ce3d8"
+        "sha": "ff01716e16d2c6e87eaf87197b753ac9fcbbed5d"
       }
     }
   ],