Build in parallel first, then install with `-j1`. This makes the build
part 3x quicker, while avoiding parallellism issues at the install
phase.
```
before after after
1da198d this
aws-lc: 1m55s ~40s
libressl: 1m16s ~1m20s
openssl-tsan: 5m47s 3m43s 1m48s (clang)
openssl: 6m38s 4m49s 2m13s (quic)
quictls-no-deprecated: 2m28s 1m51s
quictls: ~6m08s 4m16s 1m55s
wolfssl-all: 1m36s 52s
wolfssl-master: 1m34s 53s
wolfssl-opensslextra: 50s 32s
```
Follow-up to 1da198d18e#15622Closes#15630
b13078d6c5