This changes Python API tests to use a single build shared across all
test functions, instead of the previous default behavior of a separate
build dir for each test function.
This build behavior opt-out, tests can use the previous behavior of one
individual (unshared) build directory per test function, by setting
`SHARED_BUILD_TESTCASE` to False (in the test class).
The motivation is to make the test suite more efficient, by not
repeatedly building the same test source. When running tests on my macOS
machine, this reduces the time of `ninja check-lldb-api` by almost 60%
(sample numbers: from ~492s down to ~207s = 58%). Almost 5min time
saved.
Each test function still calls `self.build()`, but only the first call
will do a build, in the subsequent tests `make` will be a no-op because
the sources won't have changed.
Make SBTarget::AddModule possibly call out to an external program to
find the binary by UUID if it can't be found more easily, the same
way `target modules add -u ...` works from the commandline.
If the Target does not have an architecture set yet, use the
Module's Arch to initialize it. Allows an API writer to create
a target with no arch, and inherit it from the first binary they
load with AddModules.
Differential Revision: https://reviews.llvm.org/D157659
rdar://113657555
