[test/SourceKit] Introduce a test that ensures a certain set of arguments allows both compiler and sourcekitd invocations to share the same module cache

Author: akyrtzi

test/SourceKit/Misc/Inputs/mymod/module.modulemap

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+module mymod {
+  header "mymod.h"
+}

test/SourceKit/Misc/Inputs/mymod/mymod.h

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+void mymod_call_me(void);

test/SourceKit/Misc/match-module-cache-with-compiler.swift

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+// This test ensures a certain set of arguments allows both compiler and sourcekitd invocations to share the same module cache.
+// NOTE: Do not change this test without a review from @akyrtzi
+
+// REQUIRES: shell
+// RUN: %empty-directory(%t)
+
+// RUN: COMPILER_ARGS=( \
+// RUN:   -module-name themod \
+// RUN:   -module-cache-path %t/mcp \
+// RUN:   -sdk %sdk \
+// RUN:   -swift-version 5 \
+// RUN:   -I %S/Inputs/mymod \
+// RUN:   -Xfrontend -experimental-allow-module-with-compiler-errors \
+// RUN:   -Xcc -D__INDEX_BUILD__=1 -D__INDEX_BUILD__ \
+// RUN:   -Xcc -Xclang -Xcc -fallow-pcm-with-compiler-errors \
+// RUN:   -Xcc -Xclang -Xcc -fmodule-format=raw \
+// RUN:   -Xcc -Xclang -Xcc -detailed-preprocessing-record \
+// RUN:   %s \
+// RUN: )
+
+// RUN: %swiftc_driver -emit-module -emit-module-path themod.swiftmodule -Xfrontend -experimental-skip-all-function-bodies ${COMPILER_ARGS[@]}
+// RUN: %swiftc_driver -index-file -index-file-path %s -index-store-path %t/idx -index-ignore-system-modules ${COMPILER_ARGS[@]}
+// RUN: %sourcekitd-test -req=sema %s -- ${COMPILER_ARGS[@]}
+// RUN: find %t/mcp -name "mymod-*.pcm" | count 1
+
+import mymod