Add CompileTests for InternalImportsByDefault #1528

Job	Run time
Api Breakage Compared to main branch	1m 37s
fuzzing_regressions (debug)	3m 32s
fuzzing_regressions (release)	2m 56s
sanitizer_testing (address, debug)	2m 35s
core (5.10.1-noble, ref/heads/main)	11m 8s
sanitizer_testing (address, release)	5m 8s
core (5.9.2-focal, SWIFT_BUILD_TEST_HOOK="-Xswiftc -warnings-as-errors", ref/heads/main)	8m 37s
core (5.8.1-focal, SWIFT_BUILD_TEST_HOOK="-Xswiftc -warnings-as-errors", ref/heads/main)	8m 5s
sanitizer_testing (thread, debug)	2m 41s
sanitizer_testing (thread, release)	4m 33s
	50m 52s

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