Attempt N+1 at fixing Linux tests

Author: DougGregor

test/Interpreter/fractal.swift

@@ -1,13 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %import-libdispatch -emit-library -o %t/%target-library-name(complex) -emit-module %S/complex.swift -module-link-name complex
+// RUN: %target-build-swift -Xfrontend -disable-implicit-concurrency-module-import -emit-library -o %t/%target-library-name(complex) -emit-module %S/complex.swift -module-link-name complex
 // RUN: %target-jit-run %s -I %t -L %t | %FileCheck %s
 
 // RUN: grep -v import %s > %t/main.swift
 // RUN: %target-jit-run %t/main.swift %S/complex.swift | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_interpreter
-// REQUIRES: libdispatch
 
 import complex
 

test/Interpreter/mandelbrot.swift

@@ -1,13 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %import-libdispatch -emit-library -o %t/%target-library-name(complex) -emit-module %S/complex.swift -module-link-name complex
+// RUN: %target-build-swift -Xfrontend -disable-implicit-concurrency-module-import -emit-library -o %t/%target-library-name(complex) -emit-module %S/complex.swift -module-link-name complex
 // RUN: %target-jit-run %s -I %t -L %t | %FileCheck %s
 
 // RUN: grep -v import %s > %t/main.swift
 // RUN: %target-jit-run %t/main.swift %S/complex.swift | %FileCheck %s
 
 // REQUIRES: executable_test
 // REQUIRES: swift_interpreter
-// REQUIRES: libdispatch
 
 import complex
 

validation-test/Sanitizers/fuzzer.swift

@@ -1,9 +1,8 @@
-// RUN: %target-build-swift %import-libdispatch -parse-as-library -sanitize=fuzzer %s -o %t
+// RUN: %target-build-swift -Xfrontend -disable-implicit-concurrency-module-import -parse-as-library -sanitize=fuzzer %s -o %t
 // RUN: not %t -only_ascii=1 -max_len=3 | %FileCheck %s
 // REQUIRES: CPU=x86_64
 // REQUIRES: executable_test
 // REQUIRES: fuzzer_runtime
-// REQUIRES: libdispatch
 
 // XFAIL: OS=ios
 // XFAIL: OS=tvos