Run time errors with i2c temperature/humidity sensors

[pdgilbert]

(Possibly related to #749)

I have examples with some embedded-hal v1 temperature/humidity sensor crates that compile but then fail running. The general symptom is that they do not return from an initial call to the hal.

There are three AHT20 sensor crates and also crates for sensors SHT30 and SHTC3. I have checked the sensor crates with a git version and a release version if it exists. The crates are:

• @anglerud 's aht20-driver v2.0.0 and git https://github.com/anglerud/aht20-driver#fd81e034)
• @blueluna 's aht20 https://github.com/blueluna/aht20#07a72ca9)
• @ghismary 's embedded-aht20 v0.1.3 https://github.com/ghismary/embedded-aht20#fbeaaee0)
• @dbrgn 's shtcx-rs https://github.com/dbrgn/shtcx-rs#0cfcb5d3)
• @ghismary 's embedded-sht3x https://gitlab.com/ghislainmary/embedded-sht3x#d22db3e8)

I have tested these with stm32f4xx-hal release v0.22.1 and also with a recent git commit #ed88ea13. For comparison I have also tested with @techmccat 's stm32g4xx-hal from https://github.com/techmccat/stm32g4xx-hal#9462f4cd branch hal-1.
All examples compile with both hals (and also with stm32f1xx-hal).
The three AHT20 crates work with stm32g4xx-hal but fail with stm32f4xx-hal. The SHT30 and SHTC3 crates work with stm32f4xx-hal but fail with stm32g4xx-hal.

I have put the examples in a repository https://github.com/pdgilbert/i2c-test. The action tab shows the compiling results. The README has a few more details from GDB.
The repository also includes some examples with @eldruin 's xca9548a-rs multiplexer crate. These also compile but have run time errors (even in the cases where the sensor crates alone work).

Of course, the most likely problem is that I have something wrong in the setup (src/setup_all_stm32f4xx.rs) but I think it is correct (encouraged by the fact that some examples work). Another possibility is that sensor delays are not sufficiently long, but that would likely affect all examples.

Of course, my hope is that the cross-device abstraction can be made to work, so the device crates will work with different HALs. Suggestions would be appreciated.