Xcode 12.3 also targets Apple Silicon so it will try to build the for arm.
  Upon the frameworks that Bluepill links to, CoreSimulator has arm64e so
  Xcode would refuse to link to it. To make Bluepill build with Xcode 12.3
  here we pin ARCH to x86_64

Extracted variable DerivedDataPath in build.sh
Remoted schemes "bp-tests" and "bluepill-tests"
Changed schemes "bp" and "bluepill" to include related test targets
Changed schemes in build.sh to build and test "bp" and "bluepill" schemes
Hide bplib scheme since it's setup as a target dependency of bp and bluepill

The workflow would be:
Before doing anything, run build-for-testing (CMD+Shift+U) for BPSampleApp
Work on bp or bluepill targets, to run tests, use test button or (CMD+U)

Fixed typo

Always collect xcresult. Even when the tests fail.

Also added the collect xcresult in master workflow.

When building with Xcode with Simulator Xcode will pick the host arch. For
  now it's only x86_64
This change aligns the artifact of the sample app for CI and local dev.
We will figure out what to do with Apple Silicon when we start to support
  it.

Refactored bluepill.sh to reuse code for running tests
Changed github workflow yml's to run tests with 3 machines
Added base test case class BPIntTestCase to split BluepillTests which runs
  for an hour
Created new test case BPReportTests to extract some tests out of BluepillTests
  to run on another machine