[FrontendTool] Add test for SPI imports in module trace.

Author: varungandhi-apple

test/Driver/loaded_module_trace_spi.swift

@@ -0,0 +1,21 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -emit-module -module-name Module0 -DSPI_DECLARING_MODULE -o %t/Module0.swiftmodule
+// RUN: %target-build-swift %s -module-name Module1 -DSPI_IMPORTING_MODULE -emit-loaded-module-trace -o %t/spi_import -I %t
+// RUN: %FileCheck %s < %t/Module1.trace.json
+
+#if SPI_DECLARING_MODULE
+
+@_spi(ForModule1)
+public func f() {}
+
+#endif
+
+#if SPI_IMPORTING_MODULE
+
+@_spi(ForModule1)
+import Module0
+
+#endif
+
+// FIXME: SPI imports are marked indirect in trace.
+// CHECK: "name":"Module0","path":"{{[^"]*}}","isImportedDirectly":false