all: ignored builders for test flakes reporting

[rsc]

#!watchflakes
skip <-
	builder == "android-386-emu" ||
	builder == "android-amd64-emu" ||
	builder == "darwin-amd64-12-aws" ||
	builder == "freebsd-arm-paulzhol" ||
	builder == "linux-amd64-unified" ||
	builder == "linux-loong64-3a5000" ||
	builder == "netbsd-386-9_0" ||
	builder == "netbsd-amd64-9_0" ||
	builder == "netbsd-arm-bsiegert" ||
	builder == "netbsd-arm64-bsiegert" ||
	builder == "plan9-386" ||
	builder == "plan9-386-0intro" ||
	builder == "plan9-amd64-0intro" ||
	builder == "plan9-arm" ||
	builder == "solaris-amd64-oraclerel" ||
	builder == "windows-386-2008-newcc" ||
	builder == "windows-386-2012-newcc" ||
	builder == "windows-amd64-2008-newcc" ||
	builder == "windows-amd64-2012-newcc" ||
	builder == "windows-amd64-2016-newcc" ||
	builder == "windows-amd64-longtest-newcc" ||
	builder == "windows-amd64-newcc-race" ||
	builder == "windows-arm64-11"

This issue defines policy (above) for which builders are entirely ignored for flake finding.