46203 Reset the global variable before running a test. (cla: yes, framework)

46204 v1.12.13+hotfix.3 cherry-picks (cla: yes, engine, framework, team, tool)

46206 standardize target platform override behavior in tool and update gallery to support it (cla: yes, d: examples, team, team: gallery, tool)

46210 prevent accidental calls to io.exit when asserts are active. (cla: yes, tool)

46211 Roll engine 0506c65f5915..29998f07faf9 (6 commits) (autoroller: commit, cla: yes)

46213 Detect and dump flaky LineMetrics test data (a: tests, cla: yes, framework, team: flakes)