[macros] Fix flake: use the SDK that was actually built.

Currently these two tests only passes by chance, if a `release` build
happens to be available.

[email protected]

Change-Id: I6048c6ed8ea2f299c88eaf9a6c6b2add8a03dfa0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/356083
Auto-Submit: Morgan :) <[email protected]>
Reviewed-by: William Hesse <[email protected]>
Commit-Queue: Morgan :) <[email protected]>

Author: davidmorgan

tests/macro_build/analyzer_lt_test.dart

@@ -8,7 +8,8 @@ void main() {
   testMacroBuild([
     r'$DART pub get',
     r'$DART '
-        r'$DART_SDK/out/ReleaseX64/gen/dartanalyzer.dart.snapshot '
+        // TODO(davidmorgan): find this programmatically.
+        r'$DART_SDK/out/DebugX64/gen/dartanalyzer.dart.snapshot '
         '-Dtest_runner.configuration=analyzer-asserts-linux '
         '--enable-experiment=macros '
         '--ignore-unrecognized-flags '

tests/macro_build/cfe_lt_test.dart

@@ -12,7 +12,8 @@ void main() {
         '--verify '
         '--skip-platform-verification -o out.dill '
         '--platform '
-        r'$DART_SDK/out/ReleaseX64/vm_platform_strong.dill '
+        // TODO(davidmorgan): find this programmatically.
+        r'$DART_SDK/out/DebugX64/vm_platform_strong.dill '
         '-Dtest_runner.configuration=cfe-strong-linux '
         '--enable-experiment=macros '
         '--nnbd-strong '