[Sanitizer] Don't depend on symbolication in asan_recover.swift. (swiftlang#28290)

Relying on symbolication via `atos` unfortunately does not seem to be
a good idea because there are several testing scenarios where this
doesn't work and we fallback to `dladdr()` for Darwin platforms.

To workaround this, the `asan_recover.swift` test has been changed
to just test for the function name which covers the fully-symbolicated
and partially symbolicated case (`dladdr()` fallback). To make sure that
the two errors come from different locations (the original intention of
examining source locations) the second error has been moved into a
different function called `foo`. Unfortunately in some testing scenarios
`foo` isn't always demangled correctly so we have to make the FileCheck
pattern quite liberal.

rdar://problem/57198494

Author: danliew-apple

test/Sanitizers/asan_recover.swift

@@ -42,6 +42,11 @@ fflush(stdout)
 
 let size:Int = 128;
 
+func foo(_ rawptr:UnsafeMutablePointer<UInt8>) {
+  print("Read second element:\(rawptr.advanced(by: 1).pointee)")
+  fflush(stdout)
+}
+
 // In this test we need multiple issues to occur that ASan can detect.
 // Allocating a buffer and artificially poisoning it seems like the best way to
 // test this because there's no undefined behavior happening. Hopefully this
@@ -77,18 +82,18 @@ __asan_poison_memory_region(UnsafeMutableRawPointer(x), size)
 // NOTE: Testing for stackframe `#0` should ensure that the poison read
 // happened in instrumentation and not in an interceptor.
 // CHECK-COMMON-STDERR: AddressSanitizer: use-after-poison
-// CHECK-COMMON-STDERR: #0 0x{{.+}} in main {{.*}}asan_recover.swift:[[@LINE+1]]
+// CHECK-COMMON-STDERR: #0 0x{{.+}} in main{{.*}}
 print("Read first element:\(x.advanced(by: 0).pointee)")
 fflush(stdout)
 // CHECK-RECOVER-STDOUT: Read first element:0
 
 // Second error
+// NOTE: Very loose regex is to accomodate if name demangling
+// fails. rdar://problem/57235673
 // CHECK-RECOVER-STDERR: AddressSanitizer: use-after-poison
-// CHECK-RECOVER-STDERR: #0 0x{{.+}} in main {{.*}}asan_recover.swift:[[@LINE+1]]
-print("Read second element:\(x.advanced(by: 1).pointee)")
-fflush(stdout)
+// CHECK-RECOVER-STDERR: #0 0x{{.+}} in {{.*}}foo{{.*}}
 // CHECK-RECOVER-STDOUT: Read second element:0
-
+foo(x)
 __asan_unpoison_memory_region(UnsafeMutableRawPointer(x), size)
 
 x.deallocate();