git: fix checks by limiting build cores

building git on a 96 core machine fails during installCheckPhase

Even when limiting to 48 cores, it still fails.
32 cores seem to work.

Error on too many cores:
```
git> Test Summary Report
git> -------------------
git> t7002-mv-sparse-checkout.sh                      (Wstat: 256 (exited 1) Tests: 22 Failed: 1)
git>   Failed test:  7
git>   Non-zero exit status: 1
git> t5319-multi-pack-index.sh                        (Wstat: 256 (exited 1) Tests: 93 Failed: 1)
git>   Failed test:  11
git>   Non-zero exit status: 1
git> t5515-fetch-merge-logic.sh                       (Wstat: 256 (exited 1) Tests: 65 Failed: 1)
git>   Failed test:  31
git>   Non-zero exit status: 1
git> t7513-interpret-trailers.sh                      (Wstat: 256 (exited 1) Tests: 99 Failed: 1)
git>   Failed test:  66
git>   Non-zero exit status: 1
git> Files=1016, Tests=30358, 87 wallclock secs ( 6.47 usr  3.63 sys + 219.99 cusr 2407.64 csys = 2637.73 CPU)
git> Result: FAIL
git> make[1]: *** [Makefile:73: prove] Error 1
git> make[1]: Leaving directory '/build/git-2.49.0/t'
git> make: *** [Makefile:3274: test] Error 2
```

0 files changed, 0 insertions, 0 deletions