build: remove armv6 from experimental platforms #6325

Job	Run time
Build slim tarball	2m 20s
aarch64-linux: Cache V8 build	1h 7m 2s
x86_64-linux: with shared libraries	1h 52m 38s
x86_64-darwin: with shared libraries	2h 21m 3s
aarch64-darwin: with shared libraries	2h 14m 41s
aarch64-linux: with shared openssl-4.0.0	25m 36s
aarch64-linux: with shared openssl-1.1.1w	23m 14s
aarch64-linux: with shared openssl-3.5.5	26m 42s
aarch64-linux: with shared openssl-3.0.19	25m 40s
aarch64-linux: with shared openssl-3.6.1	23m 43s
	9h 42m 39s

Provide feedback